Elements of the balanced diet

The general ways of the metabolism of proteins lipids

and carbohydrates

Biological oxidation

Bioenergetics cells

Tverrsquo 2018

104

ELEMENTS OF THE BALANCED DIET AND THE GENERAL WAYS OF THE METABOLISM OF PROTEINS LIPIDS AND

CARBOHYDRATES

What are basic chemical elements of tissues of plants and animals

What are the ways of assimilating these elements by plants and animals

autotrophics (photosynthetic organism) use the sun energy(light) atmos-

pheric СО2 Н2О and inorganic N- and S-containing salts of earth micro-

elements synthesize carbohydrates lipids and protein which become the

food source for animals

heterotrophic one is used to oxidize carbohydrates lipids protein with

the help of oxygen synthesized by plants they are used as energy circu-

late and remove in the form of СО2 Н2О N and S ndash containing com-

pounds which transformed into inorganic salts of earth

mdash Turnover of СО2 О2 Н2О N Н and S (The circuit of a united cycle of life -

explain it)

Modern problems of ecology

SUN

Energy

12Н2О

AUTOTROPHIC

(plants and seaweeds )

6Н2О

light

6 О2 12NADPН2

6СО2 18АТP

Dark stage

stage

Light stage

12Н2О

HETEROTROPHIC

( Bacteria and animals)

Н

R Н

О2

NАDН2

АТP

СО2 Н2О

О2

proteins

lipids

carb-tes

СО2

-N

-S

Н2О

UNITED CYCLE of LIFE

NH3

N S etc

Н

R Н

105

problems of pollution by toxins of atmosphere soil water - explain

Significance of flora in preservation of life on the Earthhellip hellip

The demands to a rational diet of man

1 Irreplaceable components of food

Irreplaceable amino acids

Irreplaceable high fatty acids (linoleic linolenic arachidonic)

Irreplaceable vitamins and vitaminoids substances A Е K Q В1 В2

В3 В5 В6 В9 В12 C Р ie 13 vitamins and vitaminoids substances

Mineral components of food (macro-and microelements sodium potassi-

um calcium magnesium iron copper zinc cobalt nickel tin fluorine phosphorus

iodine selenium chlorine bromine molybdenum chromium silicon and many oth-

ers)

tissue (cellulose pectin lignin)

water

2 Quantity of calories necessary for man depending on age sex the type of nervous ac-

tivity occupation pregnancy lactation etc (2200 - 3000 kcal 9200 - 12600 kDj)

3 Rational protein fats and carbohydrates ratio in feeding

4 Significance of a dietary regimen of food reception (twice thrice four times a day)

5 Divisibility of food receipt (morning - day - evening)

6 Paying attention to individual habits and national traditions (preference of vegetative or

albuminous food keeping the fast etc)

48

12

10 10

10

polysaccharides

protein Lipids

10

Polysacharides (starch glycogen) 48

PROTEINS 12

Saturated fatty acid 10

Monounsaturated fatty acid 10

sucrose 10

Polyunsaturated fatty acid 10

CARBOHYDRATES

нууууCAR-

BODRATES

LIPIDS (FATS) sucrose

106

7 Adequacy of food structure to the organism status (diabetes - restriction of carbohy-

drates diseases of the liver kidneys - restriction of proteins atherosclerosis and IHD

- restriction of lipids etc)

8 Significance in feeding regimen of the maintenance and restoration of a constancy of

body weight

9 Significance of culinary processing of food (conservation thermal processing a pick-

les smoking and other) for protection of health

The role of carbohydrates in a diet

The basic carbohydrates of food (polysaccharides disaccharides monosaccha-

rides)

Importance of carbohydrates in a diet of people (energy source) requirement

400g per day

Main causes of prevalence of vegetative food (carbohydrates) in a diet of people

(the price of manufacture)

Dangers for peoplersquos health at increase of

The part of polysaccharides deficiency of irreplaceable components

The part of mono- and disaccharides (sucrose glucose fructose daily

requirement lt 100g) an overstrain of insulin system hyperglycemia and

other complications)

The positive and negative sides of food carbohydrates action on peoplersquos

health condition

(+) - the basic energetic material rather small need for oxygen for oxi-

dation in conditions of deficiency of oxygen it will be catalyzed ease

of their metabolism indifferent end-products of an exchange celluose

stimulate peristalsis and removal toxic products from intestines

(-) few irreplaceable components disturbance in the metabolism and de-

velopment of various diseases at changes of a rational part poly-and

mono sugars in a diet

Substitutes of refined sugars in food (saccharin aspartin monelin and others)

The role of lipids in a diet

Lipids of food in man (TG PL CH HFA) Daily requirement (80 - 100 gm)

Significance of lipids in peoplersquos diet (an energy source and irreplaceable com-

ponents of food)

High fatty acids and their biological role (precursors of hormones components

of phospholipids and triglycerides the basic depot of energy)

Triglycerides in peoplersquos diet [hard soft liquid]

Rational ratio of liquid and hard fats in peoplersquos diet =5050 (= 20-25 gm vege-

tative lipids containing nonsaturated fatty acids per day)

Significance of a person for protection health of a rational firm and liquid fats

ratio (an atherosclerosis oncological diseases etc)

The role of phospholipids in peoplersquos diet (a source of choline inozitol etc)

107

The role of cholesterol in peoplersquos diet (the daily requirement ˜ 15 gm ex-

ogenic and its endogenic sources cholesterol is a part of membranes the pre-

cursor of hormones bilious acids vitamins of group D)

The positive and negative action of lipids on peoplersquos health

(+)-resources of energy the sources of irreplaceable components and bi-

ologically active substances

(-) - oxidation needs more oxygen the excess leads to the disturbance of

their exchange hyperlipidemia and the development of a number of dis-

eases

The role of proteins in a diet

Importance of proteins in a diet (the source of nitrogen irreplaceable amino ac-

ids and energy)

Daily requirement (dependence on age occupation the condition of the organ-

ism) 80-100 gm assimilated proteins the half of them should be of the animal

origin

Chemical and biological significance of protein (amino-acids structure and the

degree of assimilation)

Protein-energy insufficiency and Kwashiorkor disease

Positive and negative action of protein excess on peoplersquos health

(+) the source of nitrogen irreplaceable amino acids energy

(-) it metabolize in a complicated mannerand end-products of disintegra-

tion of the protein - ammonia and urea - are rather toxic

Ethanol its part in peoplersquos diet

Consequences of alcohol abusing

ndash Metabolism of ethanol (90 in the liver)

Alcohol dehydrogenase acetaldehyde dehydrogenase

CH3 ndash CH2 ndash OH CH3 ndash C CH3 ndashC

HAD HADH2 H HAD HADH2 ОH acetaldehyde acetate

(toxic)

ACETYL-COA CO2 H2O АТP + heat

Metabolic premise of alcoholic dependence degradation of a personality and

occurrence of various diseases

CAС

О О

108

Average consumption of ethanol in the advanced countries is ˜10 of food in

caloric value

At abusing of alcoholic drinks the increase of the deficiency of entering irre-

placeable components of food into tissue (irreplaceable amino acids high fatty

acids vitamins mineral substances and celluose) occurs

Alcohol dehydrogenase and acetaldehyde dehydrogenase competing with other

dehydrogenases for NAD disturb many reactions of oxidation of substances in a

cell

The metabolism of proteins carbohydrates phospholipids (the rate of gluconeo-

genesis in the liver is reduced - arises hypoglycemia only triglycerides are in-

tensively synthesized in the liver- the fatty dystrophy of the liver develops) is

disodered

Because of protein metabolism disoder and other biologically active substances

in CNS - increases the degradation of a personality immunity and resistibility of

the organism that stimulates the development of many diseases reduce

Because of easiness of ethanol metabolism (only two enzymes are necessary for his

oxidation up to Acetyl - coA) the cells prefer an easy way of energy manufacture from this

product that conducts to accustoming cells to this product and finally to the dependence of

the organism on entering alcoholic drinks with food

General ways of the metabolism of protein fats and carbohydrates

The concept of metabolism (catabolism and anabolism) and metabolitics (substrates

and intermediate products of the exchange)

Stages and reactions of Catabolism of proteins fats and carbohydrates

PROTEINS CARBOHYDRATES LIPIDS

amino acids monosaccharides glycerin and high fatty acid

ketoacids

acetyl coA

Н2О + СО2 3NADH2

1FADH2

C A С (Citric Acid Cycle)

I

II

III

F o o d o f m a n

ATP + HEAT

Ethanol

109

Phases of catabolism and releasing of energy from nutrients

I-st phase - preparatory (in the gastroenteric tract) - transfer of food or endocellular bi-

opolymers into monomers

hydrolases in intestines or inside cells

significance of proteins fats and carbohydrates digestion in the gastroenteric

tract (hydrolysis and destruction of specific and antigenic specificity of food

components)

2-nd phase - (in cytoplasm of cells and in mitochondria) - formation of the universal

substrat of oxidation for CAC - Acetyl ndash coA from amino acids monosugars and high

fatty acids

Specific ways of disintegration of amino acids carbohydrates glycerin high

fatty acids and ethanol

Conditions are mainly anaerobic there is a presence of specific enzymes and

coferments (for example catabolism of glucose up to Acetyl - CoA requires 15

enzymes and ethanolndashonly 3 ferments)

6-7 of the energy involved in initial substrats become free thus the part of

energy is accumulated in high-energic АТP bond (substrate phosphorylation)

the other part dissipates as heat

3-rd phase - (in mitochondria) - full oxidation of acetyl-CoA in the Krebs cycle up to

СО2 and carrying protons and electrons with the help of NAD and FAD-dependent dehy-

drogenase in the respiratory circuit on О2 for the formation of АТPh (oxidative phosphory-

lation) and heat

Citric Acids Cycle (Krebs cycle) mdash Cyclic system of reactions

chemical reactions of a citric acids cycle (CAC) as a general mode of proteins

fats and carbohydrates catabolism

uml CAC begins with interaction of Acetyl- CoA and oxaloacetate with the

formation of the citric acid

uml Through a number of reactions isocitrate α-ketoglutarate succinate and

malate which are exposed to oxidation (dehydrogation) form oxaloacetate

again

uml During these reactions Acetyl - CoA molecule is oxidized up to 2 СО2

the coferments 3 NAD and 1 FAD are restored up to 3 NADH2 and

FADН2

110

HC - COOH

||

HC - COOH

fumarate

H2C - COOH

|

HO - C - COOH

|

H 2C - COOH

citrate

O

H3C - C

S - KoA

HS CoA

O = C - COOH

|

H2C - COOH

oxaloacetate

Н2О

H2C - COOH

|

C - COOH

||

HC - COOH

Cis-aconitate

СО2 NADН2 H2C - COOH

|

HC - COO H

|

HO - C - COOH

|

H

isocitrate

H2C - COOH

|

H2C- C - COO H

||

O

-ketoglutarate

NADН2

H2C - COOH

|

H2C - C ~ S KoA

||

O

succinyl CоА

GTP (АТP)

H2C - COOH

|

H2C - COOH

succinate

FADН2

ОН Н

HO - CH - COOH

|

H2C - COOH

malate

(малат)

NADН2

Н2О

Н S-CоА

СО2

Н2О

S CoA

proteins

lipids

carbohydrates

111

Biological role of the tricarbonoic acids cycle

integrative (amphibolic) ndash unites the catabolic and anabolic pathways of

carbohydrates lipids and proteins

catabolic and energetic ndash disintegration of Acetyl - CоА

- substrate phosphorylation in the tricarbonoic acids cycle (1

GTP = 1 АТP at the expense of the macroergs of succinyl-CоА)

- oxidative phosphorylation (3 NADН2-9 АТP

FADН2-2АТP only 11 АТP

- Total = 12 АТP

anabolic ndash substrats of the citric acid cycle are used for syn-

thesis of other substances

- oxaloacetate - aspartate glucose

ketoglutarate - glutamate

- succinyl-CоА - heme

Stages of proteins fats and carbohydrates anabolism

polysaccharides

proteins lipids

aminoacids monosaccharides

(glucose) fatty acids

ketoacids

pyruvate acetyle CoA

oxaloacetate

α-ketogluterate

succinate

Similarities and differences of processes of catabolism and anabolism (the place

of action enzymes coferments bio-energetics)

BIO-ENERGETICS of the CELL MECHANISMS of BIOLOGICAL OXIDATION

mdash The basic energy source for all organisms on the Earth is the sun radiation (as

a result of reactions of nuclear synthesis on the Sun)

III

II

I

g l y c e

r i n

112

mdash Photosynthesizing cells of plants catch the solar energy and use it on transfor-

mations of inorganic substances - СО2 Н2О and salts - in various rich energy

organic compounds (proteins lipids carbohydrates) Under the action of the

solar energy electrons of Н2О in the cells of plants are stimulated i е they

transfer (in the structure of proteins lipids carbohydrates) into higher energet-

ic level

mdash During disintegration of proteins fats and carbohydrates in an organism of an-

imals the return transition of electrons into lower power orbit with the for-

mation of Н2О take place which is accompanied by releasing the same quantity

of energy Hence the basic carrier of energy -electron and its source - the Sun

Laws of thermodynamics

Forms of energy (thermal chemical electric etc) and the communications exist-

ing between various forms of energy (opportunities of transformation) which

are formulated in the laws of thermodynamics

The first law of thermodynamics

sect Energy neither disappear nor arise it is only transforms from one form

into another

The second law of thermodynamics (entropy)

sect All spontaneous processes in the systems proceed only in one direction -

reduction of free energy that is not seldom accompanied by increase the

systems disorder (entropy)

The conditions necessary for preservation of homeostage of alive organisms

(constancy of the internal medium) ndash entering energy in it since processes of

disintegration are constantly present

Mathematical calculation of change of free energy

G = H ndash Т S where

G - a part of energy of the system which is spent for fulfillment of work

(kjulemole substances)

H -Change in heat contents of the system (enthalpy)

Т - absolute temperature

S - entropy change disorder of the systems

The energy enters animals organism in the form of proteins carbohydrates and

lipids catabolism of which conducts to becoming this energy free and its trans-

formation into

Energy of macroergs (АТP etc)

Electric energy

Thermal energy

Mechanical one

Energy of chemical bonds etc

113

High-energy (macroergs) and low-energy compounds of animals tissue АТP - universal macroergs in plants and animals world

macroergic compounds are called the substances having macroergic bond

macroergic bond is marked by ldquo~rdquo Energy is used for satisfaction of

energy needs of a cell

compound product of reaction -G kjulemole

phosphoenolpyruvate pyruvate + Н3РО4 619

13-bisphosphoglycerate 3-phosphoglycerate+Н3РО4 545

carbamoylphosphate carbamate + Н3РО4 515

creatinephosphate creatine + Н3РО4 431

pyrophosphate Н4Р2О7 2 Н3РО4 334

Acetyle-CoA acetate +HS-CоА 350

Succinyle-CoA succinate + HS-CoA 435

АТP (GTPUTP etc) ADP + Н3РО4 345 (~73 kcalmole)

ADP АМP + Н3РО4 363

АМP adenosine + Н3РО4 96

glycerophosphate glycerine + Н3РО4 92

glucose-6-phosphate glucose + Н3РО4 138

- Universal macroerg is ATP Its molecule serves as a part connecting among them-

selves various kinds of transformation of energy chemical mechanical electric

osmotic and other processes going with release and consumption of energy

- The reasons of release of energy at hydrolysis of macroergic bond (phospho-

anhydtate) of АТP and АDP

Redistribution of electrons on orbits

pH medium (neutral)

Significance of dissociation (АТP-4 АDP-3 АМP-2)

- Daily requirement of the adult for energy (АТP) and real presence АТP in an or-

ganism (˜65kg available 3-4g)

- Reactions n of АDP rephosphorylatio and subsequent use of АТP as an energy

source (dephosphorylation) form the cycle which repeats 25-3 thousand times per day

The diagram of the formation and use of АТP in an organism

Solar energy

plants cells (carbohy-

drates lipids proteins)

feeding of animals

Energy of

Carbohydrates lipids pro-

teins

АТP

АDP + Н3РО4

biosynthesis

Muscular reduction

Active transport of ions

through membranes (po-

tential of rest and potential

of action)

Other volatile processes

energydependent

(body temperature)

re

ph

osp

ho

ryla

tio

n

Dep

ho

sph

ory

latio

n

114

2 modes of ADP rephosphorylation

Oxidative phosphorylation

Substrate phosphorylation

The main substrates for rephosphorylation of АDP oxidation of proteins fats

and carbohydrates in tissues during their oxidation

Variants of oxidation of organic substances in animal tissues

oxidase type (dehydration and transport of electrons and protons on oxy-

gen with the formation of energy Н2О СО2) oxigenase (oxidations of a substrate by oxygen)

mechanisms of peroxide oxidation of lipids

peroxidase type (oxidation of a substrate with the formation of hydrogen

peroxide and use of the latter for oxidation of other substrates)

Oxidase type of oxidations of proteins lipids carbohydrates (cell respiration of

tissues) is the basic mode of oxidation in tissues of animals and at the same time it manu-

factures energy (АТP and heat)

Oxidase type of oxidation of substrates is provided with enzymes and coferments of

the respiratory circuit

Chemical compound of components of a respiratory circuit and their

redox-potential

Components of a respiratory circuit are collected from the set of enzymes and

polypeptides which contain a number of various oxidizing and restored

coferments and cofactors (iron copper) as a prostetic group

Е0В ndash042 ndash 032 + 004 + 007 + 023 + 025 + 029 + 055 + 082

Н NAD (FMN) Ко Q b Fe3+

c1 Fe3+

c Fe3+

a Fe3+

a3 (Cu2+

Fe3+

) 12O2

R

Н NADН2 Ко Q Н2 b Fe2+

c1 Fe2+

c Fe2+

a Fe2+

a3 (Cu+Fe

2+) Н2О

And also Fes protein ATP ATP ATP

cytochromes dehydrogenase

ndash 005

FAD

FADН2

(2)

(1)

115

The redox-potential is characterized by the energy which is released at transporting electrons from the given substance on a hydrogen electrode and is ex-

pressed in electron-volts

o The redox-potential and the function of components of the respiratory circuit depend on a chemical nature and correlation of the oxidized and

restored molecules included in their structure

o Members of oxidation-reduction lines settle down in ascending order of potentials [-032В - (+082В)]

o Components of the respiratory circuit in mitochondria are organized in complexes (the circuit is on page 15)

The respiratory circuit includes four albuminous complexes (I III IV V) built - in the internal mitochondrial membrane and two mobile systems mole-

cules - carriers - ubiquinone (КоQ) and cytochromes C Succinate dehydrogenase from cycle TCA is also considered as well as the complex of II respiratory

circuit

complex I ( NADН-dehydrogenase + FMN +FeS-proteins)

complex II ( succinate dehydrogenase + FAD +FeS-proteins)

complex III (cytochromendashC- reductase contents cytochromes b c1 и FeS-proteins)

complex IV (cytochrome-C- oxidase contents cytochromes а and а3 Сu)

complex V ( АТP-synthase)

electrons and protons enter the respiratory circuit in two ways

in the oxidation of NADН2 complex 1 transfers electrons and protons through FMN and FeS-protein on ubiquinone

in oxidation succinate electrons and protons are transferred on ubiquinone by complex II containing FADН2-dehydrogenase and FeS-protein

As a result in both cases the oxidized form of ubiquinone (КоQ) is restored up to ubihydrochinone (КоQН2)

Then the electrons from КоQН2 are transferred along the circuit by complex III on cytochrome C

cytochrome C transfers electrons to complex IV in which cytochrome а3 has unique properties - ability to transfer electrons on 12О2 with the for-

mation of О-2

ion which joins the protons removed from oxidized substrates through dehydrogenase and KoQ Endogenic water is formed

In the human organism as a result of cell respiration (tissue) 300 - 400 ml of water is formed for a day endogenic or metabolic water (camels in a de-

sert bears - hibernation in a den)

Complete restoration of О2 up to Н2О requires joining 4 е-

In an organism restoration of oxygen occurs stage by stage transferring 1еndash at each stage

Joining the first еndash forms superoxide anion О2

ndash

Joining two еndash forms peroxide anion О2

2ndashН2О2

Peroxide of hydrogen and superoxide radical are very toxic They are destroyed in a cell the first ndash by catalase the second ndash by superoxiddismutase

116

The organization of complexes I-V from the components of the respiratory circuit in mitochondria (scheme)

3 ADP + 3 Pi

Pro

tein

sli

pid

samp c

arb

o-

hydra

tes

of

food

АТP- synthetase

complex V complex I

NADН-dehydrogenase

FMN + FeS - protein

complex III

cytochrome c - reductase (cytochrome bc1)

and FeS - proteins

complex IV

Cytochrome C oxidase

cytochrome аа3 Cu)

КоQ

2е-+2Н

+ e-rarr

e-rarr

cytochrome

С rarre

-rarr

rarre-rarr

Ex

tern

al m

em-

bra

ne

of

mit

o-

cho

ndri

a

Inte

rnal

mem

-b

ran

e of

mit

o-

cho

ndri

a

Intercellular space

4Н2Оharr4 Н++ 4ОН

-

com

ple

x I

I

Su

ccin

ate

deh

yd

rog

enes

is

T C A

Acetyle-CoA

pyru

vat

e

acey

l-C

oA

2Н

++

2е- 4Н2Оharr4 Н

++ 4ОН

-

2Н+

4Н+

2Н

++

2е-

2Н2Оharr2 Н++ 2ОН

-

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

+ + + + + 4Н+ + + + + + + + 2Н

+ +

ОН- ОН

- ОН

-

2Н+

+12О2

12О2

2е-

Н2О

Matrix of

mitochondria

10Н+

10ОН-

10Н2О

3 А

ТP

+

hea

t NADН2

FA

DH

2

Endogenic water

(300-400 ml per day)

О2 + e- О2ˉ (superoxide anion)

О2ˉ+ e- О2

2ˉ (peroxide anion)

О2ˉ +e-+ 2H

+ H2О2 (peroxide of hydrogen)

H2О2+ О2ˉ OHˉ + OH + O2 (hydroxyle

anion and hydroxyle radical)

117

Together with electrons complexes I III and IV due to the energy of electrons

transferring of protons from mitochondrial matrix (Н + are formed at dissocia-

tion of waters) is vectorially made into intermembraneous space where the con-

centration of ions Н+ increases and on a membrane the proton potential Н +

is formed

Biological sense of electrons transport along the respira-tory circuit and transfer of protons into the intermembra-

neous space (chemiosmatic hypothesis of Mitchel -Sculachev)

Transfer of electrons along the respiratory circuit is accompanied with the

gradual releasing energy the part of which (~ 40 ) is used for the formation

of АТP and other energy dissipates as heat (heatproduction)

Energy of electrons is used for the formation of a proton gradient on the inter-

nal mitochondrial membrane The proton potential appears (an electrochemical

gradient of ions Н + Н +)

Formation of АТP (oxidative phosphorylation) entails the reverse stream of

protons from intermembraneous spaces into mitochondrial matrix however the

membrane of mitochondria is impenetrable for protons

In mitochondria only АТP- synthetase (complex V) allows to carry out the re-

verse movement of protons from intermembranal spaces in mitochondrial matrix

and the same enzyme catalyses the formation of АТP ie synthesis АТP entails

the oxidation of substrate and then coferments and cofactors of respiratory cir-

cuit with participation of oxygen Therefore this process (oxidations and phos-

phorylation of АDP with formation of АТP) has received the name of oxidative

phosphorylation

АТP- synthetase consists of two parts the proton channel (13 subunits of pro-

tein) built in the internal membrane of mitochondria and catalyzed structure

acting in mitochondrial matrix (3 α - and 3 szlig-subunits)

Cycle of formation of АТP is divided into 3 phases

Linkage with the enzyme of АDP and Р

Formation of phosphoanhydrate bond between АDP and Р with the

formation of АТP

Releasing of end-products of the reaction (АТP and waters)

Calculation of the energy educed during the transport of electrons along

the respiratory circuit

Change of free energy (G) during the transport of electrons depends only on a

difference of oxidation-reduction potentials of the donor and the acceptor of

electrons in the respiratory circuit

The general value of the energy released at transport of 2е along the respiratory

circuit can be calculated

G0 = - n F E where

118

G0 - change of free standard energy

n- the number of transferred electrons (for example we shall take 2 of them)

F ndash Faraday number = 23062 cal

mole

E ndash Difference of standard potentials of components of the respiratory cir-

cuit giving (-032 volts) and accepting (+ 082 volts) electrons

Transfer of 2 electrons is accompanied with educing

G0 = - 2 23062 [082 ndash (- 032)] = - 526

kcalmole or (237

кjulemole)

- If protons enter the intermembraneous space through complexes I III

and IV 3 molecules АТP and coefficient of phosphorylation (rela-

tion PO)= 3 are formed if protons enter only through complexes II III

and IV 2 molecules АТP and coefficient of phosphorylation (PO)

= 2 are formed where Р ndash is the quantity of the inorganic phosphate in-

cluded in 2 or 3 АТP O- atom of oxygen on which 2 e- are transferred

- The reasons of conjugation oxidation and phosphorylation (oxidative

phosphorylation) are only on 3 or 2 parts of the respiratory circuit

- On other parts the potential difference of the connected redox-systems

(energy) is insufficient for the formation of АТP in these parts energy is

releasing as heat

- Uncouples of oxidative phosphorylation promote an expenditure of

proton potential without АТP-synthetase dissociation of phosphoryla-

tion and respiration is present

- Breath increases

- Phosphorylation is suppressed

- Heat production increases

- Uncouples of respiration and phosphorylations

- thermogenins

- Free fatty acids RCOO-+ Н + (on the external part of the membrane)

RCOOH reg RCOO-+ Н + (on the internal part of the membrane)

- 24-dinitrophenol salicylates (anti-inflammatory remedies)

- Peculiarities of the formation of heat in newborns and animals born

bald and also running into hibernation (brown fat and peculiarities of

their respiratory circuit organization)

- Brown fat in newborns

- They contain more mitochondria

- They have 10 times more enzymes of respiration than phosphorylation

- Presence of thermogenins in the membrane provides dissociation of res-

piration and phosphorylation that leads to formation of a plenty of heat

warming flowing blood

Regulation of energy exchange

For a day the requirement of an organism in energy (АТP) varies

The rate of the АТP formation depends on a energy status of cells iе correla-

tion

[ATP]

[ADP] [P]

119

At rest the energy charge of a cell changes is about 09 and comes nearer to 1

unit

[АТP] + frac12 [АDP]

[АTP] [АDP] + [АMP

At use of energy (АТP) by the organism a part of АТP is hydrolized up to АDP

and Р the enrgy charge of a cell is reduced

Increase of АDP concentration automatically will increase the rate of oxidizing

phosphorylation and the formations АТP ie the respiration of mitochondria is

checked with the help of АDP This mechanism of regulation of energy ex-

change of a cell has got the name ldquothe respiratory controlrdquo - there is no res-

piration if there is no ADP in the cell

Oxidizing mode of substrate oxidation

It is catalysed with mono-and dioxygenase

monoxygenases ndashis including of 1 atom of oxygen into the oxidized

substrate and the other one into the molecule of water according to the

scheme

R RO + H2O

dioxygenases - enzymes which catalyzed the reaction - including of both atoms

of oxygen in to the oxidizing substance

R +О2 RО2

microsomal oxidation is a version of the microsomal mode (enzymes of

oxidation - cytochromes Р450 are in microsomes)

- Bile acids

- - Steroid hormones

- - Heterologous substances (drugs toxins etc)

They are oxidazed according to oxygenase mode without educing energy

H

+ O2

H

RndashН + О2 RndashОН + Н2О

2еoline

NADPН2

FAD

Fe-protein

Р450

2Н+

120

Lipid Peroxidation (LP)

Active oxygen species (НО2- peroxide radical middotО2oline - superoxide radical middotОН-

hydroxyl radical) are capable to take hydrogen away from (-СН2-) the groups of

fatty acids transforming them into (-middotСН-) groups

Such radicals easily join molecules of oxygen and become a peroxyl radical of

fatty acids

ndashmiddotСНndash + О2 ndashСНndashОndashО

middot

The radical chain reaction begins when the peroxyl radical takes a hydrogen at-

om from the other fatty acid molecule thus stimulates free radical chain re-

actions

ndashСНndashОndashОmiddot + (ndashСН2ndash) ndashСНndashОndashОН + (ndash

middotСНndash)

Nonsaturated fatty acids which turn into peroxids and hydroperoxids of li-

pids are most sensitive to Lipid Peroxidation

Products of the LP - hydroperoxids of lipids spirits aldehydes malonic alde-

hyde ketons etc

Biological significance of Lipid Peroxidation

Regulation of renovating and permeability of lipid biological mem-

branes

In phagocytic cells for destruction of the absorbed bacteria and infec-

tious material Н2О2 and a superoxide radical which initiate the LP are

used and bacteria perish

Free radical processes can completely destroy nonsaturated lipids of

biomembranes of host cells causing inevitable destruction of cells

In the membranes of cells free radical processes are limited as there are various systems of protection against active forms of oxygen (antioxidant systems) in

cells

PERIOXIDIZATION MODE

R∙H2 + O2 rarr R + H2O2

Localization in peroxysomas (about 80 of H2O2 are formed) enzymes- ox-

ydase of amino acids amines etc

Biological significance

Amino acids biogenic amines and other organic molecules are oxidized

in such a way

Thus toxic for cells of an organism hydrogen peroxide H2O2 is formed

In leukocytes H2O2 is used for neutralization of pathogenic bacteria

In cells H2O2 is neutralized with the help of enzymes (catalase [E1] peroxydase

[E2])according to the scheme

2Н2О2 2Н2О + О2

Н2О2 + R Н2О + RO

121

Protection of membranes against LP

1 Inactivization of oxygen radicals under the action of superoxide

dismutase and catalase

2 Fermentative mechanism of membrane protection against LP un-

der the action of glutathione peroxidase

3 Chemical protection of membranes against LP with the help of anti-

oxidizers (the most powerful antioxidizer is Vitamin E)

104

ELEMENTS OF THE BALANCED DIET AND THE GENERAL WAYS OF THE METABOLISM OF PROTEINS LIPIDS AND

CARBOHYDRATES

What are basic chemical elements of tissues of plants and animals

What are the ways of assimilating these elements by plants and animals

autotrophics (photosynthetic organism) use the sun energy(light) atmos-

pheric СО2 Н2О and inorganic N- and S-containing salts of earth micro-

elements synthesize carbohydrates lipids and protein which become the

food source for animals

heterotrophic one is used to oxidize carbohydrates lipids protein with

the help of oxygen synthesized by plants they are used as energy circu-

late and remove in the form of СО2 Н2О N and S ndash containing com-

pounds which transformed into inorganic salts of earth

mdash Turnover of СО2 О2 Н2О N Н and S (The circuit of a united cycle of life -

explain it)

Modern problems of ecology

SUN

Energy

12Н2О

AUTOTROPHIC

(plants and seaweeds )

6Н2О

light

6 О2 12NADPН2

6СО2 18АТP

Dark stage

stage

Light stage

12Н2О

HETEROTROPHIC

( Bacteria and animals)

Н

R Н

О2

NАDН2

АТP

СО2 Н2О

О2

proteins

lipids

carb-tes

СО2

-N

-S

Н2О

UNITED CYCLE of LIFE

NH3

N S etc

Н

R Н

105

problems of pollution by toxins of atmosphere soil water - explain

Significance of flora in preservation of life on the Earthhellip hellip

The demands to a rational diet of man

1 Irreplaceable components of food

Irreplaceable amino acids

Irreplaceable high fatty acids (linoleic linolenic arachidonic)

Irreplaceable vitamins and vitaminoids substances A Е K Q В1 В2

В3 В5 В6 В9 В12 C Р ie 13 vitamins and vitaminoids substances

Mineral components of food (macro-and microelements sodium potassi-

um calcium magnesium iron copper zinc cobalt nickel tin fluorine phosphorus

iodine selenium chlorine bromine molybdenum chromium silicon and many oth-

ers)

tissue (cellulose pectin lignin)

water

2 Quantity of calories necessary for man depending on age sex the type of nervous ac-

tivity occupation pregnancy lactation etc (2200 - 3000 kcal 9200 - 12600 kDj)

3 Rational protein fats and carbohydrates ratio in feeding

4 Significance of a dietary regimen of food reception (twice thrice four times a day)

5 Divisibility of food receipt (morning - day - evening)

6 Paying attention to individual habits and national traditions (preference of vegetative or

albuminous food keeping the fast etc)

48

12

10 10

10

polysaccharides

protein Lipids

10

Polysacharides (starch glycogen) 48

PROTEINS 12

Saturated fatty acid 10

Monounsaturated fatty acid 10

sucrose 10

Polyunsaturated fatty acid 10

CARBOHYDRATES

нууууCAR-

BODRATES

LIPIDS (FATS) sucrose

106

7 Adequacy of food structure to the organism status (diabetes - restriction of carbohy-

drates diseases of the liver kidneys - restriction of proteins atherosclerosis and IHD

- restriction of lipids etc)

8 Significance in feeding regimen of the maintenance and restoration of a constancy of

body weight

9 Significance of culinary processing of food (conservation thermal processing a pick-

les smoking and other) for protection of health

The role of carbohydrates in a diet

The basic carbohydrates of food (polysaccharides disaccharides monosaccha-

rides)

Importance of carbohydrates in a diet of people (energy source) requirement

400g per day

Main causes of prevalence of vegetative food (carbohydrates) in a diet of people

(the price of manufacture)

Dangers for peoplersquos health at increase of

The part of polysaccharides deficiency of irreplaceable components

The part of mono- and disaccharides (sucrose glucose fructose daily

requirement lt 100g) an overstrain of insulin system hyperglycemia and

other complications)

The positive and negative sides of food carbohydrates action on peoplersquos

health condition

(+) - the basic energetic material rather small need for oxygen for oxi-

dation in conditions of deficiency of oxygen it will be catalyzed ease

of their metabolism indifferent end-products of an exchange celluose

stimulate peristalsis and removal toxic products from intestines

(-) few irreplaceable components disturbance in the metabolism and de-

velopment of various diseases at changes of a rational part poly-and

mono sugars in a diet

Substitutes of refined sugars in food (saccharin aspartin monelin and others)

The role of lipids in a diet

Lipids of food in man (TG PL CH HFA) Daily requirement (80 - 100 gm)

Significance of lipids in peoplersquos diet (an energy source and irreplaceable com-

ponents of food)

High fatty acids and their biological role (precursors of hormones components

of phospholipids and triglycerides the basic depot of energy)

Triglycerides in peoplersquos diet [hard soft liquid]

Rational ratio of liquid and hard fats in peoplersquos diet =5050 (= 20-25 gm vege-

tative lipids containing nonsaturated fatty acids per day)

Significance of a person for protection health of a rational firm and liquid fats

ratio (an atherosclerosis oncological diseases etc)

The role of phospholipids in peoplersquos diet (a source of choline inozitol etc)

107

The role of cholesterol in peoplersquos diet (the daily requirement ˜ 15 gm ex-

ogenic and its endogenic sources cholesterol is a part of membranes the pre-

cursor of hormones bilious acids vitamins of group D)

The positive and negative action of lipids on peoplersquos health

(+)-resources of energy the sources of irreplaceable components and bi-

ologically active substances

(-) - oxidation needs more oxygen the excess leads to the disturbance of

their exchange hyperlipidemia and the development of a number of dis-

eases

The role of proteins in a diet

Importance of proteins in a diet (the source of nitrogen irreplaceable amino ac-

ids and energy)

Daily requirement (dependence on age occupation the condition of the organ-

ism) 80-100 gm assimilated proteins the half of them should be of the animal

origin

Chemical and biological significance of protein (amino-acids structure and the

degree of assimilation)

Protein-energy insufficiency and Kwashiorkor disease

Positive and negative action of protein excess on peoplersquos health

(+) the source of nitrogen irreplaceable amino acids energy

(-) it metabolize in a complicated mannerand end-products of disintegra-

tion of the protein - ammonia and urea - are rather toxic

Ethanol its part in peoplersquos diet

Consequences of alcohol abusing

ndash Metabolism of ethanol (90 in the liver)

Alcohol dehydrogenase acetaldehyde dehydrogenase

CH3 ndash CH2 ndash OH CH3 ndash C CH3 ndashC

HAD HADH2 H HAD HADH2 ОH acetaldehyde acetate

(toxic)

ACETYL-COA CO2 H2O АТP + heat

Metabolic premise of alcoholic dependence degradation of a personality and

occurrence of various diseases

CAС

О О

108

Average consumption of ethanol in the advanced countries is ˜10 of food in

caloric value

At abusing of alcoholic drinks the increase of the deficiency of entering irre-

placeable components of food into tissue (irreplaceable amino acids high fatty

acids vitamins mineral substances and celluose) occurs

Alcohol dehydrogenase and acetaldehyde dehydrogenase competing with other

dehydrogenases for NAD disturb many reactions of oxidation of substances in a

cell

The metabolism of proteins carbohydrates phospholipids (the rate of gluconeo-

genesis in the liver is reduced - arises hypoglycemia only triglycerides are in-

tensively synthesized in the liver- the fatty dystrophy of the liver develops) is

disodered

Because of protein metabolism disoder and other biologically active substances

in CNS - increases the degradation of a personality immunity and resistibility of

the organism that stimulates the development of many diseases reduce

Because of easiness of ethanol metabolism (only two enzymes are necessary for his

oxidation up to Acetyl - coA) the cells prefer an easy way of energy manufacture from this

product that conducts to accustoming cells to this product and finally to the dependence of

the organism on entering alcoholic drinks with food

General ways of the metabolism of protein fats and carbohydrates

The concept of metabolism (catabolism and anabolism) and metabolitics (substrates

and intermediate products of the exchange)

Stages and reactions of Catabolism of proteins fats and carbohydrates

PROTEINS CARBOHYDRATES LIPIDS

amino acids monosaccharides glycerin and high fatty acid

ketoacids

acetyl coA

Н2О + СО2 3NADH2

1FADH2

C A С (Citric Acid Cycle)

I

II

III

F o o d o f m a n

ATP + HEAT

Ethanol

109

Phases of catabolism and releasing of energy from nutrients

I-st phase - preparatory (in the gastroenteric tract) - transfer of food or endocellular bi-

opolymers into monomers

hydrolases in intestines or inside cells

significance of proteins fats and carbohydrates digestion in the gastroenteric

tract (hydrolysis and destruction of specific and antigenic specificity of food

components)

2-nd phase - (in cytoplasm of cells and in mitochondria) - formation of the universal

substrat of oxidation for CAC - Acetyl ndash coA from amino acids monosugars and high

fatty acids

Specific ways of disintegration of amino acids carbohydrates glycerin high

fatty acids and ethanol

Conditions are mainly anaerobic there is a presence of specific enzymes and

coferments (for example catabolism of glucose up to Acetyl - CoA requires 15

enzymes and ethanolndashonly 3 ferments)

6-7 of the energy involved in initial substrats become free thus the part of

energy is accumulated in high-energic АТP bond (substrate phosphorylation)

the other part dissipates as heat

3-rd phase - (in mitochondria) - full oxidation of acetyl-CoA in the Krebs cycle up to

СО2 and carrying protons and electrons with the help of NAD and FAD-dependent dehy-

drogenase in the respiratory circuit on О2 for the formation of АТPh (oxidative phosphory-

lation) and heat

Citric Acids Cycle (Krebs cycle) mdash Cyclic system of reactions

chemical reactions of a citric acids cycle (CAC) as a general mode of proteins

fats and carbohydrates catabolism

uml CAC begins with interaction of Acetyl- CoA and oxaloacetate with the

formation of the citric acid

uml Through a number of reactions isocitrate α-ketoglutarate succinate and

malate which are exposed to oxidation (dehydrogation) form oxaloacetate

again

uml During these reactions Acetyl - CoA molecule is oxidized up to 2 СО2

the coferments 3 NAD and 1 FAD are restored up to 3 NADH2 and

FADН2

110

HC - COOH

||

HC - COOH

fumarate

H2C - COOH

|

HO - C - COOH

|

H 2C - COOH

citrate

O

H3C - C

S - KoA

HS CoA

O = C - COOH

|

H2C - COOH

oxaloacetate

Н2О

H2C - COOH

|

C - COOH

||

HC - COOH

Cis-aconitate

СО2 NADН2 H2C - COOH

|

HC - COO H

|

HO - C - COOH

|

H

isocitrate

H2C - COOH

|

H2C- C - COO H

||

O

-ketoglutarate

NADН2

H2C - COOH

|

H2C - C ~ S KoA

||

O

succinyl CоА

GTP (АТP)

H2C - COOH

|

H2C - COOH

succinate

FADН2

ОН Н

HO - CH - COOH

|

H2C - COOH

malate

(малат)

NADН2

Н2О

Н S-CоА

СО2

Н2О

S CoA

proteins

lipids

carbohydrates

111

Biological role of the tricarbonoic acids cycle

integrative (amphibolic) ndash unites the catabolic and anabolic pathways of

carbohydrates lipids and proteins

catabolic and energetic ndash disintegration of Acetyl - CоА

- substrate phosphorylation in the tricarbonoic acids cycle (1

GTP = 1 АТP at the expense of the macroergs of succinyl-CоА)

- oxidative phosphorylation (3 NADН2-9 АТP

FADН2-2АТP only 11 АТP

- Total = 12 АТP

anabolic ndash substrats of the citric acid cycle are used for syn-

thesis of other substances

- oxaloacetate - aspartate glucose

ketoglutarate - glutamate

- succinyl-CоА - heme

Stages of proteins fats and carbohydrates anabolism

polysaccharides

proteins lipids

aminoacids monosaccharides

(glucose) fatty acids

ketoacids

pyruvate acetyle CoA

oxaloacetate

α-ketogluterate

succinate

Similarities and differences of processes of catabolism and anabolism (the place

of action enzymes coferments bio-energetics)

BIO-ENERGETICS of the CELL MECHANISMS of BIOLOGICAL OXIDATION

mdash The basic energy source for all organisms on the Earth is the sun radiation (as

a result of reactions of nuclear synthesis on the Sun)

III

II

I

g l y c e

r i n

112

mdash Photosynthesizing cells of plants catch the solar energy and use it on transfor-

mations of inorganic substances - СО2 Н2О and salts - in various rich energy

organic compounds (proteins lipids carbohydrates) Under the action of the

solar energy electrons of Н2О in the cells of plants are stimulated i е they

transfer (in the structure of proteins lipids carbohydrates) into higher energet-

ic level

mdash During disintegration of proteins fats and carbohydrates in an organism of an-

imals the return transition of electrons into lower power orbit with the for-

mation of Н2О take place which is accompanied by releasing the same quantity

of energy Hence the basic carrier of energy -electron and its source - the Sun

Laws of thermodynamics

Forms of energy (thermal chemical electric etc) and the communications exist-

ing between various forms of energy (opportunities of transformation) which

are formulated in the laws of thermodynamics

The first law of thermodynamics

sect Energy neither disappear nor arise it is only transforms from one form

into another

The second law of thermodynamics (entropy)

sect All spontaneous processes in the systems proceed only in one direction -

reduction of free energy that is not seldom accompanied by increase the

systems disorder (entropy)

The conditions necessary for preservation of homeostage of alive organisms

(constancy of the internal medium) ndash entering energy in it since processes of

disintegration are constantly present

Mathematical calculation of change of free energy

G = H ndash Т S where

G - a part of energy of the system which is spent for fulfillment of work

(kjulemole substances)

H -Change in heat contents of the system (enthalpy)

Т - absolute temperature

S - entropy change disorder of the systems

The energy enters animals organism in the form of proteins carbohydrates and

lipids catabolism of which conducts to becoming this energy free and its trans-

formation into

Energy of macroergs (АТP etc)

Electric energy

Thermal energy

Mechanical one

Energy of chemical bonds etc

113

High-energy (macroergs) and low-energy compounds of animals tissue АТP - universal macroergs in plants and animals world

macroergic compounds are called the substances having macroergic bond

macroergic bond is marked by ldquo~rdquo Energy is used for satisfaction of

energy needs of a cell

compound product of reaction -G kjulemole

phosphoenolpyruvate pyruvate + Н3РО4 619

13-bisphosphoglycerate 3-phosphoglycerate+Н3РО4 545

carbamoylphosphate carbamate + Н3РО4 515

creatinephosphate creatine + Н3РО4 431

pyrophosphate Н4Р2О7 2 Н3РО4 334

Acetyle-CoA acetate +HS-CоА 350

Succinyle-CoA succinate + HS-CoA 435

АТP (GTPUTP etc) ADP + Н3РО4 345 (~73 kcalmole)

ADP АМP + Н3РО4 363

АМP adenosine + Н3РО4 96

glycerophosphate glycerine + Н3РО4 92

glucose-6-phosphate glucose + Н3РО4 138

- Universal macroerg is ATP Its molecule serves as a part connecting among them-

selves various kinds of transformation of energy chemical mechanical electric

osmotic and other processes going with release and consumption of energy

- The reasons of release of energy at hydrolysis of macroergic bond (phospho-

anhydtate) of АТP and АDP

Redistribution of electrons on orbits

pH medium (neutral)

Significance of dissociation (АТP-4 АDP-3 АМP-2)

- Daily requirement of the adult for energy (АТP) and real presence АТP in an or-

ganism (˜65kg available 3-4g)

- Reactions n of АDP rephosphorylatio and subsequent use of АТP as an energy

source (dephosphorylation) form the cycle which repeats 25-3 thousand times per day

The diagram of the formation and use of АТP in an organism

Solar energy

plants cells (carbohy-

drates lipids proteins)

feeding of animals

Energy of

Carbohydrates lipids pro-

teins

АТP

АDP + Н3РО4

biosynthesis

Muscular reduction

Active transport of ions

through membranes (po-

tential of rest and potential

of action)

Other volatile processes

energydependent

(body temperature)

re

ph

osp

ho

ryla

tio

n

Dep

ho

sph

ory

latio

n

114

2 modes of ADP rephosphorylation

Oxidative phosphorylation

Substrate phosphorylation

The main substrates for rephosphorylation of АDP oxidation of proteins fats

and carbohydrates in tissues during their oxidation

Variants of oxidation of organic substances in animal tissues

oxidase type (dehydration and transport of electrons and protons on oxy-

gen with the formation of energy Н2О СО2) oxigenase (oxidations of a substrate by oxygen)

mechanisms of peroxide oxidation of lipids

peroxidase type (oxidation of a substrate with the formation of hydrogen

peroxide and use of the latter for oxidation of other substrates)

Oxidase type of oxidations of proteins lipids carbohydrates (cell respiration of

tissues) is the basic mode of oxidation in tissues of animals and at the same time it manu-

factures energy (АТP and heat)

Oxidase type of oxidation of substrates is provided with enzymes and coferments of

the respiratory circuit

Chemical compound of components of a respiratory circuit and their

redox-potential

Components of a respiratory circuit are collected from the set of enzymes and

polypeptides which contain a number of various oxidizing and restored

coferments and cofactors (iron copper) as a prostetic group

Е0В ndash042 ndash 032 + 004 + 007 + 023 + 025 + 029 + 055 + 082

Н NAD (FMN) Ко Q b Fe3+

c1 Fe3+

c Fe3+

a Fe3+

a3 (Cu2+

Fe3+

) 12O2

R

Н NADН2 Ко Q Н2 b Fe2+

c1 Fe2+

c Fe2+

a Fe2+

a3 (Cu+Fe

2+) Н2О

And also Fes protein ATP ATP ATP

cytochromes dehydrogenase

ndash 005

FAD

FADН2

(2)

(1)

115

The redox-potential is characterized by the energy which is released at transporting electrons from the given substance on a hydrogen electrode and is ex-

pressed in electron-volts

o The redox-potential and the function of components of the respiratory circuit depend on a chemical nature and correlation of the oxidized and

restored molecules included in their structure

o Members of oxidation-reduction lines settle down in ascending order of potentials [-032В - (+082В)]

o Components of the respiratory circuit in mitochondria are organized in complexes (the circuit is on page 15)

The respiratory circuit includes four albuminous complexes (I III IV V) built - in the internal mitochondrial membrane and two mobile systems mole-

cules - carriers - ubiquinone (КоQ) and cytochromes C Succinate dehydrogenase from cycle TCA is also considered as well as the complex of II respiratory

circuit

complex I ( NADН-dehydrogenase + FMN +FeS-proteins)

complex II ( succinate dehydrogenase + FAD +FeS-proteins)

complex III (cytochromendashC- reductase contents cytochromes b c1 и FeS-proteins)

complex IV (cytochrome-C- oxidase contents cytochromes а and а3 Сu)

complex V ( АТP-synthase)

electrons and protons enter the respiratory circuit in two ways

in the oxidation of NADН2 complex 1 transfers electrons and protons through FMN and FeS-protein on ubiquinone

in oxidation succinate electrons and protons are transferred on ubiquinone by complex II containing FADН2-dehydrogenase and FeS-protein

As a result in both cases the oxidized form of ubiquinone (КоQ) is restored up to ubihydrochinone (КоQН2)

Then the electrons from КоQН2 are transferred along the circuit by complex III on cytochrome C

cytochrome C transfers electrons to complex IV in which cytochrome а3 has unique properties - ability to transfer electrons on 12О2 with the for-

mation of О-2

ion which joins the protons removed from oxidized substrates through dehydrogenase and KoQ Endogenic water is formed

In the human organism as a result of cell respiration (tissue) 300 - 400 ml of water is formed for a day endogenic or metabolic water (camels in a de-

sert bears - hibernation in a den)

Complete restoration of О2 up to Н2О requires joining 4 е-

In an organism restoration of oxygen occurs stage by stage transferring 1еndash at each stage

Joining the first еndash forms superoxide anion О2

ndash

Joining two еndash forms peroxide anion О2

2ndashН2О2

Peroxide of hydrogen and superoxide radical are very toxic They are destroyed in a cell the first ndash by catalase the second ndash by superoxiddismutase

116

The organization of complexes I-V from the components of the respiratory circuit in mitochondria (scheme)

3 ADP + 3 Pi

Pro

tein

sli

pid

samp c

arb

o-

hydra

tes

of

food

АТP- synthetase

complex V complex I

NADН-dehydrogenase

FMN + FeS - protein

complex III

cytochrome c - reductase (cytochrome bc1)

and FeS - proteins

complex IV

Cytochrome C oxidase

cytochrome аа3 Cu)

КоQ

2е-+2Н

+ e-rarr

e-rarr

cytochrome

С rarre

-rarr

rarre-rarr

Ex

tern

al m

em-

bra

ne

of

mit

o-

cho

ndri

a

Inte

rnal

mem

-b

ran

e of

mit

o-

cho

ndri

a

Intercellular space

4Н2Оharr4 Н++ 4ОН

-

com

ple

x I

I

Su

ccin

ate

deh

yd

rog

enes

is

T C A

Acetyle-CoA

pyru

vat

e

acey

l-C

oA

2Н

++

2е- 4Н2Оharr4 Н

++ 4ОН

-

2Н+

4Н+

2Н

++

2е-

2Н2Оharr2 Н++ 2ОН

-

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

+ + + + + 4Н+ + + + + + + + 2Н

+ +

ОН- ОН

- ОН

-

2Н+

+12О2

12О2

2е-

Н2О

Matrix of

mitochondria

10Н+

10ОН-

10Н2О

3 А

ТP

+

hea

t NADН2

FA

DH

2

Endogenic water

(300-400 ml per day)

О2 + e- О2ˉ (superoxide anion)

О2ˉ+ e- О2

2ˉ (peroxide anion)

О2ˉ +e-+ 2H

+ H2О2 (peroxide of hydrogen)

H2О2+ О2ˉ OHˉ + OH + O2 (hydroxyle

anion and hydroxyle radical)

117

Together with electrons complexes I III and IV due to the energy of electrons

transferring of protons from mitochondrial matrix (Н + are formed at dissocia-

tion of waters) is vectorially made into intermembraneous space where the con-

centration of ions Н+ increases and on a membrane the proton potential Н +

is formed

Biological sense of electrons transport along the respira-tory circuit and transfer of protons into the intermembra-

neous space (chemiosmatic hypothesis of Mitchel -Sculachev)

Transfer of electrons along the respiratory circuit is accompanied with the

gradual releasing energy the part of which (~ 40 ) is used for the formation

of АТP and other energy dissipates as heat (heatproduction)

Energy of electrons is used for the formation of a proton gradient on the inter-

nal mitochondrial membrane The proton potential appears (an electrochemical

gradient of ions Н + Н +)

Formation of АТP (oxidative phosphorylation) entails the reverse stream of

protons from intermembraneous spaces into mitochondrial matrix however the

membrane of mitochondria is impenetrable for protons

In mitochondria only АТP- synthetase (complex V) allows to carry out the re-

verse movement of protons from intermembranal spaces in mitochondrial matrix

and the same enzyme catalyses the formation of АТP ie synthesis АТP entails

the oxidation of substrate and then coferments and cofactors of respiratory cir-

cuit with participation of oxygen Therefore this process (oxidations and phos-

phorylation of АDP with formation of АТP) has received the name of oxidative

phosphorylation

АТP- synthetase consists of two parts the proton channel (13 subunits of pro-

tein) built in the internal membrane of mitochondria and catalyzed structure

acting in mitochondrial matrix (3 α - and 3 szlig-subunits)

Cycle of formation of АТP is divided into 3 phases

Linkage with the enzyme of АDP and Р

Formation of phosphoanhydrate bond between АDP and Р with the

formation of АТP

Releasing of end-products of the reaction (АТP and waters)

Calculation of the energy educed during the transport of electrons along

the respiratory circuit

Change of free energy (G) during the transport of electrons depends only on a

difference of oxidation-reduction potentials of the donor and the acceptor of

electrons in the respiratory circuit

The general value of the energy released at transport of 2е along the respiratory

circuit can be calculated

G0 = - n F E where

118

G0 - change of free standard energy

n- the number of transferred electrons (for example we shall take 2 of them)

F ndash Faraday number = 23062 cal

mole

E ndash Difference of standard potentials of components of the respiratory cir-

cuit giving (-032 volts) and accepting (+ 082 volts) electrons

Transfer of 2 electrons is accompanied with educing

G0 = - 2 23062 [082 ndash (- 032)] = - 526

kcalmole or (237

кjulemole)

- If protons enter the intermembraneous space through complexes I III

and IV 3 molecules АТP and coefficient of phosphorylation (rela-

tion PO)= 3 are formed if protons enter only through complexes II III

and IV 2 molecules АТP and coefficient of phosphorylation (PO)

= 2 are formed where Р ndash is the quantity of the inorganic phosphate in-

cluded in 2 or 3 АТP O- atom of oxygen on which 2 e- are transferred

- The reasons of conjugation oxidation and phosphorylation (oxidative

phosphorylation) are only on 3 or 2 parts of the respiratory circuit

- On other parts the potential difference of the connected redox-systems

(energy) is insufficient for the formation of АТP in these parts energy is

releasing as heat

- Uncouples of oxidative phosphorylation promote an expenditure of

proton potential without АТP-synthetase dissociation of phosphoryla-

tion and respiration is present

- Breath increases

- Phosphorylation is suppressed

- Heat production increases

- Uncouples of respiration and phosphorylations

- thermogenins

- Free fatty acids RCOO-+ Н + (on the external part of the membrane)

RCOOH reg RCOO-+ Н + (on the internal part of the membrane)

- 24-dinitrophenol salicylates (anti-inflammatory remedies)

- Peculiarities of the formation of heat in newborns and animals born

bald and also running into hibernation (brown fat and peculiarities of

their respiratory circuit organization)

- Brown fat in newborns

- They contain more mitochondria

- They have 10 times more enzymes of respiration than phosphorylation

- Presence of thermogenins in the membrane provides dissociation of res-

piration and phosphorylation that leads to formation of a plenty of heat

warming flowing blood

Regulation of energy exchange

For a day the requirement of an organism in energy (АТP) varies

The rate of the АТP formation depends on a energy status of cells iе correla-

tion

[ATP]

[ADP] [P]

119

At rest the energy charge of a cell changes is about 09 and comes nearer to 1

unit

[АТP] + frac12 [АDP]

[АTP] [АDP] + [АMP

At use of energy (АТP) by the organism a part of АТP is hydrolized up to АDP

and Р the enrgy charge of a cell is reduced

Increase of АDP concentration automatically will increase the rate of oxidizing

phosphorylation and the formations АТP ie the respiration of mitochondria is

checked with the help of АDP This mechanism of regulation of energy ex-

change of a cell has got the name ldquothe respiratory controlrdquo - there is no res-

piration if there is no ADP in the cell

Oxidizing mode of substrate oxidation

It is catalysed with mono-and dioxygenase

monoxygenases ndashis including of 1 atom of oxygen into the oxidized

substrate and the other one into the molecule of water according to the

scheme

R RO + H2O

dioxygenases - enzymes which catalyzed the reaction - including of both atoms

of oxygen in to the oxidizing substance

R +О2 RО2

microsomal oxidation is a version of the microsomal mode (enzymes of

oxidation - cytochromes Р450 are in microsomes)

- Bile acids

- - Steroid hormones

- - Heterologous substances (drugs toxins etc)

They are oxidazed according to oxygenase mode without educing energy

H

+ O2

H

RndashН + О2 RndashОН + Н2О

2еoline

NADPН2

FAD

Fe-protein

Р450

2Н+

120

Lipid Peroxidation (LP)

Active oxygen species (НО2- peroxide radical middotО2oline - superoxide radical middotОН-

hydroxyl radical) are capable to take hydrogen away from (-СН2-) the groups of

fatty acids transforming them into (-middotСН-) groups

Such radicals easily join molecules of oxygen and become a peroxyl radical of

fatty acids

ndashmiddotСНndash + О2 ndashСНndashОndashО

middot

The radical chain reaction begins when the peroxyl radical takes a hydrogen at-

om from the other fatty acid molecule thus stimulates free radical chain re-

actions

ndashСНndashОndashОmiddot + (ndashСН2ndash) ndashСНndashОndashОН + (ndash

middotСНndash)

Nonsaturated fatty acids which turn into peroxids and hydroperoxids of li-

pids are most sensitive to Lipid Peroxidation

Products of the LP - hydroperoxids of lipids spirits aldehydes malonic alde-

hyde ketons etc

Biological significance of Lipid Peroxidation

Regulation of renovating and permeability of lipid biological mem-

branes

In phagocytic cells for destruction of the absorbed bacteria and infec-

tious material Н2О2 and a superoxide radical which initiate the LP are

used and bacteria perish

Free radical processes can completely destroy nonsaturated lipids of

biomembranes of host cells causing inevitable destruction of cells

In the membranes of cells free radical processes are limited as there are various systems of protection against active forms of oxygen (antioxidant systems) in

cells

PERIOXIDIZATION MODE

R∙H2 + O2 rarr R + H2O2

Localization in peroxysomas (about 80 of H2O2 are formed) enzymes- ox-

ydase of amino acids amines etc

Biological significance

Amino acids biogenic amines and other organic molecules are oxidized

in such a way

Thus toxic for cells of an organism hydrogen peroxide H2O2 is formed

In leukocytes H2O2 is used for neutralization of pathogenic bacteria

In cells H2O2 is neutralized with the help of enzymes (catalase [E1] peroxydase

[E2])according to the scheme

2Н2О2 2Н2О + О2

Н2О2 + R Н2О + RO

121

Protection of membranes against LP

1 Inactivization of oxygen radicals under the action of superoxide

dismutase and catalase

2 Fermentative mechanism of membrane protection against LP un-

der the action of glutathione peroxidase

3 Chemical protection of membranes against LP with the help of anti-

oxidizers (the most powerful antioxidizer is Vitamin E)

105

problems of pollution by toxins of atmosphere soil water - explain

Significance of flora in preservation of life on the Earthhellip hellip

The demands to a rational diet of man

1 Irreplaceable components of food

Irreplaceable amino acids

Irreplaceable high fatty acids (linoleic linolenic arachidonic)

Irreplaceable vitamins and vitaminoids substances A Е K Q В1 В2

В3 В5 В6 В9 В12 C Р ie 13 vitamins and vitaminoids substances

Mineral components of food (macro-and microelements sodium potassi-

um calcium magnesium iron copper zinc cobalt nickel tin fluorine phosphorus

iodine selenium chlorine bromine molybdenum chromium silicon and many oth-

ers)

tissue (cellulose pectin lignin)

water

2 Quantity of calories necessary for man depending on age sex the type of nervous ac-

tivity occupation pregnancy lactation etc (2200 - 3000 kcal 9200 - 12600 kDj)

3 Rational protein fats and carbohydrates ratio in feeding

4 Significance of a dietary regimen of food reception (twice thrice four times a day)

5 Divisibility of food receipt (morning - day - evening)

6 Paying attention to individual habits and national traditions (preference of vegetative or

albuminous food keeping the fast etc)

48

12

10 10

10

polysaccharides

protein Lipids

10

Polysacharides (starch glycogen) 48

PROTEINS 12

Saturated fatty acid 10

Monounsaturated fatty acid 10

sucrose 10

Polyunsaturated fatty acid 10

CARBOHYDRATES

нууууCAR-

BODRATES

LIPIDS (FATS) sucrose

106

7 Adequacy of food structure to the organism status (diabetes - restriction of carbohy-

drates diseases of the liver kidneys - restriction of proteins atherosclerosis and IHD

- restriction of lipids etc)

8 Significance in feeding regimen of the maintenance and restoration of a constancy of

body weight

9 Significance of culinary processing of food (conservation thermal processing a pick-

les smoking and other) for protection of health

The role of carbohydrates in a diet

The basic carbohydrates of food (polysaccharides disaccharides monosaccha-

rides)

Importance of carbohydrates in a diet of people (energy source) requirement

400g per day

Main causes of prevalence of vegetative food (carbohydrates) in a diet of people

(the price of manufacture)

Dangers for peoplersquos health at increase of

The part of polysaccharides deficiency of irreplaceable components

The part of mono- and disaccharides (sucrose glucose fructose daily

requirement lt 100g) an overstrain of insulin system hyperglycemia and

other complications)

The positive and negative sides of food carbohydrates action on peoplersquos

health condition

(+) - the basic energetic material rather small need for oxygen for oxi-

dation in conditions of deficiency of oxygen it will be catalyzed ease

of their metabolism indifferent end-products of an exchange celluose

stimulate peristalsis and removal toxic products from intestines

(-) few irreplaceable components disturbance in the metabolism and de-

velopment of various diseases at changes of a rational part poly-and

mono sugars in a diet

Substitutes of refined sugars in food (saccharin aspartin monelin and others)

The role of lipids in a diet

Lipids of food in man (TG PL CH HFA) Daily requirement (80 - 100 gm)

Significance of lipids in peoplersquos diet (an energy source and irreplaceable com-

ponents of food)

High fatty acids and their biological role (precursors of hormones components

of phospholipids and triglycerides the basic depot of energy)

Triglycerides in peoplersquos diet [hard soft liquid]

Rational ratio of liquid and hard fats in peoplersquos diet =5050 (= 20-25 gm vege-

tative lipids containing nonsaturated fatty acids per day)

Significance of a person for protection health of a rational firm and liquid fats

ratio (an atherosclerosis oncological diseases etc)

The role of phospholipids in peoplersquos diet (a source of choline inozitol etc)

107

The role of cholesterol in peoplersquos diet (the daily requirement ˜ 15 gm ex-

ogenic and its endogenic sources cholesterol is a part of membranes the pre-

cursor of hormones bilious acids vitamins of group D)

The positive and negative action of lipids on peoplersquos health

(+)-resources of energy the sources of irreplaceable components and bi-

ologically active substances

(-) - oxidation needs more oxygen the excess leads to the disturbance of

their exchange hyperlipidemia and the development of a number of dis-

eases

The role of proteins in a diet

Importance of proteins in a diet (the source of nitrogen irreplaceable amino ac-

ids and energy)

Daily requirement (dependence on age occupation the condition of the organ-

ism) 80-100 gm assimilated proteins the half of them should be of the animal

origin

Chemical and biological significance of protein (amino-acids structure and the

degree of assimilation)

Protein-energy insufficiency and Kwashiorkor disease

Positive and negative action of protein excess on peoplersquos health

(+) the source of nitrogen irreplaceable amino acids energy

(-) it metabolize in a complicated mannerand end-products of disintegra-

tion of the protein - ammonia and urea - are rather toxic

Ethanol its part in peoplersquos diet

Consequences of alcohol abusing

ndash Metabolism of ethanol (90 in the liver)

Alcohol dehydrogenase acetaldehyde dehydrogenase

CH3 ndash CH2 ndash OH CH3 ndash C CH3 ndashC

HAD HADH2 H HAD HADH2 ОH acetaldehyde acetate

(toxic)

ACETYL-COA CO2 H2O АТP + heat

Metabolic premise of alcoholic dependence degradation of a personality and

occurrence of various diseases

CAС

О О

108

Average consumption of ethanol in the advanced countries is ˜10 of food in

caloric value

At abusing of alcoholic drinks the increase of the deficiency of entering irre-

placeable components of food into tissue (irreplaceable amino acids high fatty

acids vitamins mineral substances and celluose) occurs

Alcohol dehydrogenase and acetaldehyde dehydrogenase competing with other

dehydrogenases for NAD disturb many reactions of oxidation of substances in a

cell

The metabolism of proteins carbohydrates phospholipids (the rate of gluconeo-

genesis in the liver is reduced - arises hypoglycemia only triglycerides are in-

tensively synthesized in the liver- the fatty dystrophy of the liver develops) is

disodered

Because of protein metabolism disoder and other biologically active substances

in CNS - increases the degradation of a personality immunity and resistibility of

the organism that stimulates the development of many diseases reduce

Because of easiness of ethanol metabolism (only two enzymes are necessary for his

oxidation up to Acetyl - coA) the cells prefer an easy way of energy manufacture from this

product that conducts to accustoming cells to this product and finally to the dependence of

the organism on entering alcoholic drinks with food

General ways of the metabolism of protein fats and carbohydrates

The concept of metabolism (catabolism and anabolism) and metabolitics (substrates

and intermediate products of the exchange)

Stages and reactions of Catabolism of proteins fats and carbohydrates

PROTEINS CARBOHYDRATES LIPIDS

amino acids monosaccharides glycerin and high fatty acid

ketoacids

acetyl coA

Н2О + СО2 3NADH2

1FADH2

C A С (Citric Acid Cycle)

I

II

III

F o o d o f m a n

ATP + HEAT

Ethanol

109

Phases of catabolism and releasing of energy from nutrients

I-st phase - preparatory (in the gastroenteric tract) - transfer of food or endocellular bi-

opolymers into monomers

hydrolases in intestines or inside cells

significance of proteins fats and carbohydrates digestion in the gastroenteric

tract (hydrolysis and destruction of specific and antigenic specificity of food

components)

2-nd phase - (in cytoplasm of cells and in mitochondria) - formation of the universal

substrat of oxidation for CAC - Acetyl ndash coA from amino acids monosugars and high

fatty acids

Specific ways of disintegration of amino acids carbohydrates glycerin high

fatty acids and ethanol

Conditions are mainly anaerobic there is a presence of specific enzymes and

coferments (for example catabolism of glucose up to Acetyl - CoA requires 15

enzymes and ethanolndashonly 3 ferments)

6-7 of the energy involved in initial substrats become free thus the part of

energy is accumulated in high-energic АТP bond (substrate phosphorylation)

the other part dissipates as heat

3-rd phase - (in mitochondria) - full oxidation of acetyl-CoA in the Krebs cycle up to

СО2 and carrying protons and electrons with the help of NAD and FAD-dependent dehy-

drogenase in the respiratory circuit on О2 for the formation of АТPh (oxidative phosphory-

lation) and heat

Citric Acids Cycle (Krebs cycle) mdash Cyclic system of reactions

chemical reactions of a citric acids cycle (CAC) as a general mode of proteins

fats and carbohydrates catabolism

uml CAC begins with interaction of Acetyl- CoA and oxaloacetate with the

formation of the citric acid

uml Through a number of reactions isocitrate α-ketoglutarate succinate and

malate which are exposed to oxidation (dehydrogation) form oxaloacetate

again

uml During these reactions Acetyl - CoA molecule is oxidized up to 2 СО2

the coferments 3 NAD and 1 FAD are restored up to 3 NADH2 and

FADН2

110

HC - COOH

||

HC - COOH

fumarate

H2C - COOH

|

HO - C - COOH

|

H 2C - COOH

citrate

O

H3C - C

S - KoA

HS CoA

O = C - COOH

|

H2C - COOH

oxaloacetate

Н2О

H2C - COOH

|

C - COOH

||

HC - COOH

Cis-aconitate

СО2 NADН2 H2C - COOH

|

HC - COO H

|

HO - C - COOH

|

H

isocitrate

H2C - COOH

|

H2C- C - COO H

||

O

-ketoglutarate

NADН2

H2C - COOH

|

H2C - C ~ S KoA

||

O

succinyl CоА

GTP (АТP)

H2C - COOH

|

H2C - COOH

succinate

FADН2

ОН Н

HO - CH - COOH

|

H2C - COOH

malate

(малат)

NADН2

Н2О

Н S-CоА

СО2

Н2О

S CoA

proteins

lipids

carbohydrates

111

Biological role of the tricarbonoic acids cycle

integrative (amphibolic) ndash unites the catabolic and anabolic pathways of

carbohydrates lipids and proteins

catabolic and energetic ndash disintegration of Acetyl - CоА

- substrate phosphorylation in the tricarbonoic acids cycle (1

GTP = 1 АТP at the expense of the macroergs of succinyl-CоА)

- oxidative phosphorylation (3 NADН2-9 АТP

FADН2-2АТP only 11 АТP

- Total = 12 АТP

anabolic ndash substrats of the citric acid cycle are used for syn-

thesis of other substances

- oxaloacetate - aspartate glucose

ketoglutarate - glutamate

- succinyl-CоА - heme

Stages of proteins fats and carbohydrates anabolism

polysaccharides

proteins lipids

aminoacids monosaccharides

(glucose) fatty acids

ketoacids

pyruvate acetyle CoA

oxaloacetate

α-ketogluterate

succinate

Similarities and differences of processes of catabolism and anabolism (the place

of action enzymes coferments bio-energetics)

BIO-ENERGETICS of the CELL MECHANISMS of BIOLOGICAL OXIDATION

mdash The basic energy source for all organisms on the Earth is the sun radiation (as

a result of reactions of nuclear synthesis on the Sun)

III

II

I

g l y c e

r i n

112

mdash Photosynthesizing cells of plants catch the solar energy and use it on transfor-

mations of inorganic substances - СО2 Н2О and salts - in various rich energy

organic compounds (proteins lipids carbohydrates) Under the action of the

solar energy electrons of Н2О in the cells of plants are stimulated i е they

transfer (in the structure of proteins lipids carbohydrates) into higher energet-

ic level

mdash During disintegration of proteins fats and carbohydrates in an organism of an-

imals the return transition of electrons into lower power orbit with the for-

mation of Н2О take place which is accompanied by releasing the same quantity

of energy Hence the basic carrier of energy -electron and its source - the Sun

Laws of thermodynamics

Forms of energy (thermal chemical electric etc) and the communications exist-

ing between various forms of energy (opportunities of transformation) which

are formulated in the laws of thermodynamics

The first law of thermodynamics

sect Energy neither disappear nor arise it is only transforms from one form

into another

The second law of thermodynamics (entropy)

sect All spontaneous processes in the systems proceed only in one direction -

reduction of free energy that is not seldom accompanied by increase the

systems disorder (entropy)

The conditions necessary for preservation of homeostage of alive organisms

(constancy of the internal medium) ndash entering energy in it since processes of

disintegration are constantly present

Mathematical calculation of change of free energy

G = H ndash Т S where

G - a part of energy of the system which is spent for fulfillment of work

(kjulemole substances)

H -Change in heat contents of the system (enthalpy)

Т - absolute temperature

S - entropy change disorder of the systems

The energy enters animals organism in the form of proteins carbohydrates and

lipids catabolism of which conducts to becoming this energy free and its trans-

formation into

Energy of macroergs (АТP etc)

Electric energy

Thermal energy

Mechanical one

Energy of chemical bonds etc

113

High-energy (macroergs) and low-energy compounds of animals tissue АТP - universal macroergs in plants and animals world

macroergic compounds are called the substances having macroergic bond

macroergic bond is marked by ldquo~rdquo Energy is used for satisfaction of

energy needs of a cell

compound product of reaction -G kjulemole

phosphoenolpyruvate pyruvate + Н3РО4 619

13-bisphosphoglycerate 3-phosphoglycerate+Н3РО4 545

carbamoylphosphate carbamate + Н3РО4 515

creatinephosphate creatine + Н3РО4 431

pyrophosphate Н4Р2О7 2 Н3РО4 334

Acetyle-CoA acetate +HS-CоА 350

Succinyle-CoA succinate + HS-CoA 435

АТP (GTPUTP etc) ADP + Н3РО4 345 (~73 kcalmole)

ADP АМP + Н3РО4 363

АМP adenosine + Н3РО4 96

glycerophosphate glycerine + Н3РО4 92

glucose-6-phosphate glucose + Н3РО4 138

- Universal macroerg is ATP Its molecule serves as a part connecting among them-

selves various kinds of transformation of energy chemical mechanical electric

osmotic and other processes going with release and consumption of energy

- The reasons of release of energy at hydrolysis of macroergic bond (phospho-

anhydtate) of АТP and АDP

Redistribution of electrons on orbits

pH medium (neutral)

Significance of dissociation (АТP-4 АDP-3 АМP-2)

- Daily requirement of the adult for energy (АТP) and real presence АТP in an or-

ganism (˜65kg available 3-4g)

- Reactions n of АDP rephosphorylatio and subsequent use of АТP as an energy

source (dephosphorylation) form the cycle which repeats 25-3 thousand times per day

The diagram of the formation and use of АТP in an organism

Solar energy

plants cells (carbohy-

drates lipids proteins)

feeding of animals

Energy of

Carbohydrates lipids pro-

teins

АТP

АDP + Н3РО4

biosynthesis

Muscular reduction

Active transport of ions

through membranes (po-

tential of rest and potential

of action)

Other volatile processes

energydependent

(body temperature)

re

ph

osp

ho

ryla

tio

n

Dep

ho

sph

ory

latio

n

114

2 modes of ADP rephosphorylation

Oxidative phosphorylation

Substrate phosphorylation

The main substrates for rephosphorylation of АDP oxidation of proteins fats

and carbohydrates in tissues during their oxidation

Variants of oxidation of organic substances in animal tissues

oxidase type (dehydration and transport of electrons and protons on oxy-

gen with the formation of energy Н2О СО2) oxigenase (oxidations of a substrate by oxygen)

mechanisms of peroxide oxidation of lipids

peroxidase type (oxidation of a substrate with the formation of hydrogen

peroxide and use of the latter for oxidation of other substrates)

Oxidase type of oxidations of proteins lipids carbohydrates (cell respiration of

tissues) is the basic mode of oxidation in tissues of animals and at the same time it manu-

factures energy (АТP and heat)

Oxidase type of oxidation of substrates is provided with enzymes and coferments of

the respiratory circuit

Chemical compound of components of a respiratory circuit and their

redox-potential

Components of a respiratory circuit are collected from the set of enzymes and

polypeptides which contain a number of various oxidizing and restored

coferments and cofactors (iron copper) as a prostetic group

Е0В ndash042 ndash 032 + 004 + 007 + 023 + 025 + 029 + 055 + 082

Н NAD (FMN) Ко Q b Fe3+

c1 Fe3+

c Fe3+

a Fe3+

a3 (Cu2+

Fe3+

) 12O2

R

Н NADН2 Ко Q Н2 b Fe2+

c1 Fe2+

c Fe2+

a Fe2+

a3 (Cu+Fe

2+) Н2О

And also Fes protein ATP ATP ATP

cytochromes dehydrogenase

ndash 005

FAD

FADН2

(2)

(1)

115

The redox-potential is characterized by the energy which is released at transporting electrons from the given substance on a hydrogen electrode and is ex-

pressed in electron-volts

o The redox-potential and the function of components of the respiratory circuit depend on a chemical nature and correlation of the oxidized and

restored molecules included in their structure

o Members of oxidation-reduction lines settle down in ascending order of potentials [-032В - (+082В)]

o Components of the respiratory circuit in mitochondria are organized in complexes (the circuit is on page 15)

The respiratory circuit includes four albuminous complexes (I III IV V) built - in the internal mitochondrial membrane and two mobile systems mole-

cules - carriers - ubiquinone (КоQ) and cytochromes C Succinate dehydrogenase from cycle TCA is also considered as well as the complex of II respiratory

circuit

complex I ( NADН-dehydrogenase + FMN +FeS-proteins)

complex II ( succinate dehydrogenase + FAD +FeS-proteins)

complex III (cytochromendashC- reductase contents cytochromes b c1 и FeS-proteins)

complex IV (cytochrome-C- oxidase contents cytochromes а and а3 Сu)

complex V ( АТP-synthase)

electrons and protons enter the respiratory circuit in two ways

in the oxidation of NADН2 complex 1 transfers electrons and protons through FMN and FeS-protein on ubiquinone

in oxidation succinate electrons and protons are transferred on ubiquinone by complex II containing FADН2-dehydrogenase and FeS-protein

As a result in both cases the oxidized form of ubiquinone (КоQ) is restored up to ubihydrochinone (КоQН2)

Then the electrons from КоQН2 are transferred along the circuit by complex III on cytochrome C

cytochrome C transfers electrons to complex IV in which cytochrome а3 has unique properties - ability to transfer electrons on 12О2 with the for-

mation of О-2

ion which joins the protons removed from oxidized substrates through dehydrogenase and KoQ Endogenic water is formed

In the human organism as a result of cell respiration (tissue) 300 - 400 ml of water is formed for a day endogenic or metabolic water (camels in a de-

sert bears - hibernation in a den)

Complete restoration of О2 up to Н2О requires joining 4 е-

In an organism restoration of oxygen occurs stage by stage transferring 1еndash at each stage

Joining the first еndash forms superoxide anion О2

ndash

Joining two еndash forms peroxide anion О2

2ndashН2О2

Peroxide of hydrogen and superoxide radical are very toxic They are destroyed in a cell the first ndash by catalase the second ndash by superoxiddismutase

116

The organization of complexes I-V from the components of the respiratory circuit in mitochondria (scheme)

3 ADP + 3 Pi

Pro

tein

sli

pid

samp c

arb

o-

hydra

tes

of

food

АТP- synthetase

complex V complex I

NADН-dehydrogenase

FMN + FeS - protein

complex III

cytochrome c - reductase (cytochrome bc1)

and FeS - proteins

complex IV

Cytochrome C oxidase

cytochrome аа3 Cu)

КоQ

2е-+2Н

+ e-rarr

e-rarr

cytochrome

С rarre

-rarr

rarre-rarr

Ex

tern

al m

em-

bra

ne

of

mit

o-

cho

ndri

a

Inte

rnal

mem

-b

ran

e of

mit

o-

cho

ndri

a

Intercellular space

4Н2Оharr4 Н++ 4ОН

-

com

ple

x I

I

Su

ccin

ate

deh

yd

rog

enes

is

T C A

Acetyle-CoA

pyru

vat

e

acey

l-C

oA

2Н

++

2е- 4Н2Оharr4 Н

++ 4ОН

-

2Н+

4Н+

2Н

++

2е-

2Н2Оharr2 Н++ 2ОН

-

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

+ + + + + 4Н+ + + + + + + + 2Н

+ +

ОН- ОН

- ОН

-

2Н+

+12О2

12О2

2е-

Н2О

Matrix of

mitochondria

10Н+

10ОН-

10Н2О

3 А

ТP

+

hea

t NADН2

FA

DH

2

Endogenic water

(300-400 ml per day)

О2 + e- О2ˉ (superoxide anion)

О2ˉ+ e- О2

2ˉ (peroxide anion)

О2ˉ +e-+ 2H

+ H2О2 (peroxide of hydrogen)

H2О2+ О2ˉ OHˉ + OH + O2 (hydroxyle

anion and hydroxyle radical)

117

Together with electrons complexes I III and IV due to the energy of electrons

transferring of protons from mitochondrial matrix (Н + are formed at dissocia-

tion of waters) is vectorially made into intermembraneous space where the con-

centration of ions Н+ increases and on a membrane the proton potential Н +

is formed

Biological sense of electrons transport along the respira-tory circuit and transfer of protons into the intermembra-

neous space (chemiosmatic hypothesis of Mitchel -Sculachev)

Transfer of electrons along the respiratory circuit is accompanied with the

gradual releasing energy the part of which (~ 40 ) is used for the formation

of АТP and other energy dissipates as heat (heatproduction)

Energy of electrons is used for the formation of a proton gradient on the inter-

nal mitochondrial membrane The proton potential appears (an electrochemical

gradient of ions Н + Н +)

Formation of АТP (oxidative phosphorylation) entails the reverse stream of

protons from intermembraneous spaces into mitochondrial matrix however the

membrane of mitochondria is impenetrable for protons

In mitochondria only АТP- synthetase (complex V) allows to carry out the re-

verse movement of protons from intermembranal spaces in mitochondrial matrix

and the same enzyme catalyses the formation of АТP ie synthesis АТP entails

the oxidation of substrate and then coferments and cofactors of respiratory cir-

cuit with participation of oxygen Therefore this process (oxidations and phos-

phorylation of АDP with formation of АТP) has received the name of oxidative

phosphorylation

АТP- synthetase consists of two parts the proton channel (13 subunits of pro-

tein) built in the internal membrane of mitochondria and catalyzed structure

acting in mitochondrial matrix (3 α - and 3 szlig-subunits)

Cycle of formation of АТP is divided into 3 phases

Linkage with the enzyme of АDP and Р

Formation of phosphoanhydrate bond between АDP and Р with the

formation of АТP

Releasing of end-products of the reaction (АТP and waters)

Calculation of the energy educed during the transport of electrons along

the respiratory circuit

Change of free energy (G) during the transport of electrons depends only on a

difference of oxidation-reduction potentials of the donor and the acceptor of

electrons in the respiratory circuit

The general value of the energy released at transport of 2е along the respiratory

circuit can be calculated

G0 = - n F E where

118

G0 - change of free standard energy

n- the number of transferred electrons (for example we shall take 2 of them)

F ndash Faraday number = 23062 cal

mole

E ndash Difference of standard potentials of components of the respiratory cir-

cuit giving (-032 volts) and accepting (+ 082 volts) electrons

Transfer of 2 electrons is accompanied with educing

G0 = - 2 23062 [082 ndash (- 032)] = - 526

kcalmole or (237

кjulemole)

- If protons enter the intermembraneous space through complexes I III

and IV 3 molecules АТP and coefficient of phosphorylation (rela-

tion PO)= 3 are formed if protons enter only through complexes II III

and IV 2 molecules АТP and coefficient of phosphorylation (PO)

= 2 are formed where Р ndash is the quantity of the inorganic phosphate in-

cluded in 2 or 3 АТP O- atom of oxygen on which 2 e- are transferred

- The reasons of conjugation oxidation and phosphorylation (oxidative

phosphorylation) are only on 3 or 2 parts of the respiratory circuit

- On other parts the potential difference of the connected redox-systems

(energy) is insufficient for the formation of АТP in these parts energy is

releasing as heat

- Uncouples of oxidative phosphorylation promote an expenditure of

proton potential without АТP-synthetase dissociation of phosphoryla-

tion and respiration is present

- Breath increases

- Phosphorylation is suppressed

- Heat production increases

- Uncouples of respiration and phosphorylations

- thermogenins

- Free fatty acids RCOO-+ Н + (on the external part of the membrane)

RCOOH reg RCOO-+ Н + (on the internal part of the membrane)

- 24-dinitrophenol salicylates (anti-inflammatory remedies)

- Peculiarities of the formation of heat in newborns and animals born

bald and also running into hibernation (brown fat and peculiarities of

their respiratory circuit organization)

- Brown fat in newborns

- They contain more mitochondria

- They have 10 times more enzymes of respiration than phosphorylation

- Presence of thermogenins in the membrane provides dissociation of res-

piration and phosphorylation that leads to formation of a plenty of heat

warming flowing blood

Regulation of energy exchange

For a day the requirement of an organism in energy (АТP) varies

The rate of the АТP formation depends on a energy status of cells iе correla-

tion

[ATP]

[ADP] [P]

119

At rest the energy charge of a cell changes is about 09 and comes nearer to 1

unit

[АТP] + frac12 [АDP]

[АTP] [АDP] + [АMP

At use of energy (АТP) by the organism a part of АТP is hydrolized up to АDP

and Р the enrgy charge of a cell is reduced

Increase of АDP concentration automatically will increase the rate of oxidizing

phosphorylation and the formations АТP ie the respiration of mitochondria is

checked with the help of АDP This mechanism of regulation of energy ex-

change of a cell has got the name ldquothe respiratory controlrdquo - there is no res-

piration if there is no ADP in the cell

Oxidizing mode of substrate oxidation

It is catalysed with mono-and dioxygenase

monoxygenases ndashis including of 1 atom of oxygen into the oxidized

substrate and the other one into the molecule of water according to the

scheme

R RO + H2O

dioxygenases - enzymes which catalyzed the reaction - including of both atoms

of oxygen in to the oxidizing substance

R +О2 RО2

microsomal oxidation is a version of the microsomal mode (enzymes of

oxidation - cytochromes Р450 are in microsomes)

- Bile acids

- - Steroid hormones

- - Heterologous substances (drugs toxins etc)

They are oxidazed according to oxygenase mode without educing energy

H

+ O2

H

RndashН + О2 RndashОН + Н2О

2еoline

NADPН2

FAD

Fe-protein

Р450

2Н+

120

Lipid Peroxidation (LP)

Active oxygen species (НО2- peroxide radical middotО2oline - superoxide radical middotОН-

hydroxyl radical) are capable to take hydrogen away from (-СН2-) the groups of

fatty acids transforming them into (-middotСН-) groups

Such radicals easily join molecules of oxygen and become a peroxyl radical of

fatty acids

ndashmiddotСНndash + О2 ndashСНndashОndashО

middot

The radical chain reaction begins when the peroxyl radical takes a hydrogen at-

om from the other fatty acid molecule thus stimulates free radical chain re-

actions

ndashСНndashОndashОmiddot + (ndashСН2ndash) ndashСНndashОndashОН + (ndash

middotСНndash)

Nonsaturated fatty acids which turn into peroxids and hydroperoxids of li-

pids are most sensitive to Lipid Peroxidation

Products of the LP - hydroperoxids of lipids spirits aldehydes malonic alde-

hyde ketons etc

Biological significance of Lipid Peroxidation

Regulation of renovating and permeability of lipid biological mem-

branes

In phagocytic cells for destruction of the absorbed bacteria and infec-

tious material Н2О2 and a superoxide radical which initiate the LP are

used and bacteria perish

Free radical processes can completely destroy nonsaturated lipids of

biomembranes of host cells causing inevitable destruction of cells

In the membranes of cells free radical processes are limited as there are various systems of protection against active forms of oxygen (antioxidant systems) in

cells

PERIOXIDIZATION MODE

R∙H2 + O2 rarr R + H2O2

Localization in peroxysomas (about 80 of H2O2 are formed) enzymes- ox-

ydase of amino acids amines etc

Biological significance

Amino acids biogenic amines and other organic molecules are oxidized

in such a way

Thus toxic for cells of an organism hydrogen peroxide H2O2 is formed

In leukocytes H2O2 is used for neutralization of pathogenic bacteria

In cells H2O2 is neutralized with the help of enzymes (catalase [E1] peroxydase

[E2])according to the scheme

2Н2О2 2Н2О + О2

Н2О2 + R Н2О + RO

121

Protection of membranes against LP

1 Inactivization of oxygen radicals under the action of superoxide

dismutase and catalase

2 Fermentative mechanism of membrane protection against LP un-

der the action of glutathione peroxidase

3 Chemical protection of membranes against LP with the help of anti-

oxidizers (the most powerful antioxidizer is Vitamin E)

106

7 Adequacy of food structure to the organism status (diabetes - restriction of carbohy-

drates diseases of the liver kidneys - restriction of proteins atherosclerosis and IHD

- restriction of lipids etc)

8 Significance in feeding regimen of the maintenance and restoration of a constancy of

body weight

9 Significance of culinary processing of food (conservation thermal processing a pick-

les smoking and other) for protection of health

The role of carbohydrates in a diet

The basic carbohydrates of food (polysaccharides disaccharides monosaccha-

rides)

Importance of carbohydrates in a diet of people (energy source) requirement

400g per day

Main causes of prevalence of vegetative food (carbohydrates) in a diet of people

(the price of manufacture)

Dangers for peoplersquos health at increase of

The part of polysaccharides deficiency of irreplaceable components

The part of mono- and disaccharides (sucrose glucose fructose daily

requirement lt 100g) an overstrain of insulin system hyperglycemia and

other complications)

The positive and negative sides of food carbohydrates action on peoplersquos

health condition

(+) - the basic energetic material rather small need for oxygen for oxi-

dation in conditions of deficiency of oxygen it will be catalyzed ease

of their metabolism indifferent end-products of an exchange celluose

stimulate peristalsis and removal toxic products from intestines

(-) few irreplaceable components disturbance in the metabolism and de-

velopment of various diseases at changes of a rational part poly-and

mono sugars in a diet

Substitutes of refined sugars in food (saccharin aspartin monelin and others)

The role of lipids in a diet

Lipids of food in man (TG PL CH HFA) Daily requirement (80 - 100 gm)

Significance of lipids in peoplersquos diet (an energy source and irreplaceable com-

ponents of food)

High fatty acids and their biological role (precursors of hormones components

of phospholipids and triglycerides the basic depot of energy)

Triglycerides in peoplersquos diet [hard soft liquid]

Rational ratio of liquid and hard fats in peoplersquos diet =5050 (= 20-25 gm vege-

tative lipids containing nonsaturated fatty acids per day)

Significance of a person for protection health of a rational firm and liquid fats

ratio (an atherosclerosis oncological diseases etc)

The role of phospholipids in peoplersquos diet (a source of choline inozitol etc)

107

The role of cholesterol in peoplersquos diet (the daily requirement ˜ 15 gm ex-

ogenic and its endogenic sources cholesterol is a part of membranes the pre-

cursor of hormones bilious acids vitamins of group D)

The positive and negative action of lipids on peoplersquos health

(+)-resources of energy the sources of irreplaceable components and bi-

ologically active substances

(-) - oxidation needs more oxygen the excess leads to the disturbance of

their exchange hyperlipidemia and the development of a number of dis-

eases

The role of proteins in a diet

Importance of proteins in a diet (the source of nitrogen irreplaceable amino ac-

ids and energy)

Daily requirement (dependence on age occupation the condition of the organ-

ism) 80-100 gm assimilated proteins the half of them should be of the animal

origin

Chemical and biological significance of protein (amino-acids structure and the

degree of assimilation)

Protein-energy insufficiency and Kwashiorkor disease

Positive and negative action of protein excess on peoplersquos health

(+) the source of nitrogen irreplaceable amino acids energy

(-) it metabolize in a complicated mannerand end-products of disintegra-

tion of the protein - ammonia and urea - are rather toxic

Ethanol its part in peoplersquos diet

Consequences of alcohol abusing

ndash Metabolism of ethanol (90 in the liver)

Alcohol dehydrogenase acetaldehyde dehydrogenase

CH3 ndash CH2 ndash OH CH3 ndash C CH3 ndashC

HAD HADH2 H HAD HADH2 ОH acetaldehyde acetate

(toxic)

ACETYL-COA CO2 H2O АТP + heat

Metabolic premise of alcoholic dependence degradation of a personality and

occurrence of various diseases

CAС

О О

108

Average consumption of ethanol in the advanced countries is ˜10 of food in

caloric value

At abusing of alcoholic drinks the increase of the deficiency of entering irre-

placeable components of food into tissue (irreplaceable amino acids high fatty

acids vitamins mineral substances and celluose) occurs

Alcohol dehydrogenase and acetaldehyde dehydrogenase competing with other

dehydrogenases for NAD disturb many reactions of oxidation of substances in a

cell

The metabolism of proteins carbohydrates phospholipids (the rate of gluconeo-

genesis in the liver is reduced - arises hypoglycemia only triglycerides are in-

tensively synthesized in the liver- the fatty dystrophy of the liver develops) is

disodered

Because of protein metabolism disoder and other biologically active substances

in CNS - increases the degradation of a personality immunity and resistibility of

the organism that stimulates the development of many diseases reduce

Because of easiness of ethanol metabolism (only two enzymes are necessary for his

oxidation up to Acetyl - coA) the cells prefer an easy way of energy manufacture from this

product that conducts to accustoming cells to this product and finally to the dependence of

the organism on entering alcoholic drinks with food

General ways of the metabolism of protein fats and carbohydrates

The concept of metabolism (catabolism and anabolism) and metabolitics (substrates

and intermediate products of the exchange)

Stages and reactions of Catabolism of proteins fats and carbohydrates

PROTEINS CARBOHYDRATES LIPIDS

amino acids monosaccharides glycerin and high fatty acid

ketoacids

acetyl coA

Н2О + СО2 3NADH2

1FADH2

C A С (Citric Acid Cycle)

I

II

III

F o o d o f m a n

ATP + HEAT

Ethanol

109

Phases of catabolism and releasing of energy from nutrients

I-st phase - preparatory (in the gastroenteric tract) - transfer of food or endocellular bi-

opolymers into monomers

hydrolases in intestines or inside cells

significance of proteins fats and carbohydrates digestion in the gastroenteric

tract (hydrolysis and destruction of specific and antigenic specificity of food

components)

2-nd phase - (in cytoplasm of cells and in mitochondria) - formation of the universal

substrat of oxidation for CAC - Acetyl ndash coA from amino acids monosugars and high

fatty acids

Specific ways of disintegration of amino acids carbohydrates glycerin high

fatty acids and ethanol

Conditions are mainly anaerobic there is a presence of specific enzymes and

coferments (for example catabolism of glucose up to Acetyl - CoA requires 15

enzymes and ethanolndashonly 3 ferments)

6-7 of the energy involved in initial substrats become free thus the part of

energy is accumulated in high-energic АТP bond (substrate phosphorylation)

the other part dissipates as heat

3-rd phase - (in mitochondria) - full oxidation of acetyl-CoA in the Krebs cycle up to

СО2 and carrying protons and electrons with the help of NAD and FAD-dependent dehy-

drogenase in the respiratory circuit on О2 for the formation of АТPh (oxidative phosphory-

lation) and heat

Citric Acids Cycle (Krebs cycle) mdash Cyclic system of reactions

chemical reactions of a citric acids cycle (CAC) as a general mode of proteins

fats and carbohydrates catabolism

uml CAC begins with interaction of Acetyl- CoA and oxaloacetate with the

formation of the citric acid

uml Through a number of reactions isocitrate α-ketoglutarate succinate and

malate which are exposed to oxidation (dehydrogation) form oxaloacetate

again

uml During these reactions Acetyl - CoA molecule is oxidized up to 2 СО2

the coferments 3 NAD and 1 FAD are restored up to 3 NADH2 and

FADН2

110

HC - COOH

||

HC - COOH

fumarate

H2C - COOH

|

HO - C - COOH

|

H 2C - COOH

citrate

O

H3C - C

S - KoA

HS CoA

O = C - COOH

|

H2C - COOH

oxaloacetate

Н2О

H2C - COOH

|

C - COOH

||

HC - COOH

Cis-aconitate

СО2 NADН2 H2C - COOH

|

HC - COO H

|

HO - C - COOH

|

H

isocitrate

H2C - COOH

|

H2C- C - COO H

||

O

-ketoglutarate

NADН2

H2C - COOH

|

H2C - C ~ S KoA

||

O

succinyl CоА

GTP (АТP)

H2C - COOH

|

H2C - COOH

succinate

FADН2

ОН Н

HO - CH - COOH

|

H2C - COOH

malate

(малат)

NADН2

Н2О

Н S-CоА

СО2

Н2О

S CoA

proteins

lipids

carbohydrates

111

Biological role of the tricarbonoic acids cycle

integrative (amphibolic) ndash unites the catabolic and anabolic pathways of

carbohydrates lipids and proteins

catabolic and energetic ndash disintegration of Acetyl - CоА

- substrate phosphorylation in the tricarbonoic acids cycle (1

GTP = 1 АТP at the expense of the macroergs of succinyl-CоА)

- oxidative phosphorylation (3 NADН2-9 АТP

FADН2-2АТP only 11 АТP

- Total = 12 АТP

anabolic ndash substrats of the citric acid cycle are used for syn-

thesis of other substances

- oxaloacetate - aspartate glucose

ketoglutarate - glutamate

- succinyl-CоА - heme

Stages of proteins fats and carbohydrates anabolism

polysaccharides

proteins lipids

aminoacids monosaccharides

(glucose) fatty acids

ketoacids

pyruvate acetyle CoA

oxaloacetate

α-ketogluterate

succinate

Similarities and differences of processes of catabolism and anabolism (the place

of action enzymes coferments bio-energetics)

BIO-ENERGETICS of the CELL MECHANISMS of BIOLOGICAL OXIDATION

mdash The basic energy source for all organisms on the Earth is the sun radiation (as

a result of reactions of nuclear synthesis on the Sun)

III

II

I

g l y c e

r i n

112

mdash Photosynthesizing cells of plants catch the solar energy and use it on transfor-

mations of inorganic substances - СО2 Н2О and salts - in various rich energy

organic compounds (proteins lipids carbohydrates) Under the action of the

solar energy electrons of Н2О in the cells of plants are stimulated i е they

transfer (in the structure of proteins lipids carbohydrates) into higher energet-

ic level

mdash During disintegration of proteins fats and carbohydrates in an organism of an-

imals the return transition of electrons into lower power orbit with the for-

mation of Н2О take place which is accompanied by releasing the same quantity

of energy Hence the basic carrier of energy -electron and its source - the Sun

Laws of thermodynamics

Forms of energy (thermal chemical electric etc) and the communications exist-

ing between various forms of energy (opportunities of transformation) which

are formulated in the laws of thermodynamics

The first law of thermodynamics

sect Energy neither disappear nor arise it is only transforms from one form

into another

The second law of thermodynamics (entropy)

sect All spontaneous processes in the systems proceed only in one direction -

reduction of free energy that is not seldom accompanied by increase the

systems disorder (entropy)

The conditions necessary for preservation of homeostage of alive organisms

(constancy of the internal medium) ndash entering energy in it since processes of

disintegration are constantly present

Mathematical calculation of change of free energy

G = H ndash Т S where

G - a part of energy of the system which is spent for fulfillment of work

(kjulemole substances)

H -Change in heat contents of the system (enthalpy)

Т - absolute temperature

S - entropy change disorder of the systems

The energy enters animals organism in the form of proteins carbohydrates and

lipids catabolism of which conducts to becoming this energy free and its trans-

formation into

Energy of macroergs (АТP etc)

Electric energy

Thermal energy

Mechanical one

Energy of chemical bonds etc

113

High-energy (macroergs) and low-energy compounds of animals tissue АТP - universal macroergs in plants and animals world

macroergic compounds are called the substances having macroergic bond

macroergic bond is marked by ldquo~rdquo Energy is used for satisfaction of

energy needs of a cell

compound product of reaction -G kjulemole

phosphoenolpyruvate pyruvate + Н3РО4 619

13-bisphosphoglycerate 3-phosphoglycerate+Н3РО4 545

carbamoylphosphate carbamate + Н3РО4 515

creatinephosphate creatine + Н3РО4 431

pyrophosphate Н4Р2О7 2 Н3РО4 334

Acetyle-CoA acetate +HS-CоА 350

Succinyle-CoA succinate + HS-CoA 435

АТP (GTPUTP etc) ADP + Н3РО4 345 (~73 kcalmole)

ADP АМP + Н3РО4 363

АМP adenosine + Н3РО4 96

glycerophosphate glycerine + Н3РО4 92

glucose-6-phosphate glucose + Н3РО4 138

- Universal macroerg is ATP Its molecule serves as a part connecting among them-

selves various kinds of transformation of energy chemical mechanical electric

osmotic and other processes going with release and consumption of energy

- The reasons of release of energy at hydrolysis of macroergic bond (phospho-

anhydtate) of АТP and АDP

Redistribution of electrons on orbits

pH medium (neutral)

Significance of dissociation (АТP-4 АDP-3 АМP-2)

- Daily requirement of the adult for energy (АТP) and real presence АТP in an or-

ganism (˜65kg available 3-4g)

- Reactions n of АDP rephosphorylatio and subsequent use of АТP as an energy

source (dephosphorylation) form the cycle which repeats 25-3 thousand times per day

The diagram of the formation and use of АТP in an organism

Solar energy

plants cells (carbohy-

drates lipids proteins)

feeding of animals

Energy of

Carbohydrates lipids pro-

teins

АТP

АDP + Н3РО4

biosynthesis

Muscular reduction

Active transport of ions

through membranes (po-

tential of rest and potential

of action)

Other volatile processes

energydependent

(body temperature)

re

ph

osp

ho

ryla

tio

n

Dep

ho

sph

ory

latio

n

114

2 modes of ADP rephosphorylation

Oxidative phosphorylation

Substrate phosphorylation

The main substrates for rephosphorylation of АDP oxidation of proteins fats

and carbohydrates in tissues during their oxidation

Variants of oxidation of organic substances in animal tissues

oxidase type (dehydration and transport of electrons and protons on oxy-

gen with the formation of energy Н2О СО2) oxigenase (oxidations of a substrate by oxygen)

mechanisms of peroxide oxidation of lipids

peroxidase type (oxidation of a substrate with the formation of hydrogen

peroxide and use of the latter for oxidation of other substrates)

Oxidase type of oxidations of proteins lipids carbohydrates (cell respiration of

tissues) is the basic mode of oxidation in tissues of animals and at the same time it manu-

factures energy (АТP and heat)

Oxidase type of oxidation of substrates is provided with enzymes and coferments of

the respiratory circuit

Chemical compound of components of a respiratory circuit and their

redox-potential

Components of a respiratory circuit are collected from the set of enzymes and

polypeptides which contain a number of various oxidizing and restored

coferments and cofactors (iron copper) as a prostetic group

Е0В ndash042 ndash 032 + 004 + 007 + 023 + 025 + 029 + 055 + 082

Н NAD (FMN) Ко Q b Fe3+

c1 Fe3+

c Fe3+

a Fe3+

a3 (Cu2+

Fe3+

) 12O2

R

Н NADН2 Ко Q Н2 b Fe2+

c1 Fe2+

c Fe2+

a Fe2+

a3 (Cu+Fe

2+) Н2О

And also Fes protein ATP ATP ATP

cytochromes dehydrogenase

ndash 005

FAD

FADН2

(2)

(1)

115

The redox-potential is characterized by the energy which is released at transporting electrons from the given substance on a hydrogen electrode and is ex-

pressed in electron-volts

o The redox-potential and the function of components of the respiratory circuit depend on a chemical nature and correlation of the oxidized and

restored molecules included in their structure

o Members of oxidation-reduction lines settle down in ascending order of potentials [-032В - (+082В)]

o Components of the respiratory circuit in mitochondria are organized in complexes (the circuit is on page 15)

The respiratory circuit includes four albuminous complexes (I III IV V) built - in the internal mitochondrial membrane and two mobile systems mole-

cules - carriers - ubiquinone (КоQ) and cytochromes C Succinate dehydrogenase from cycle TCA is also considered as well as the complex of II respiratory

circuit

complex I ( NADН-dehydrogenase + FMN +FeS-proteins)

complex II ( succinate dehydrogenase + FAD +FeS-proteins)

complex III (cytochromendashC- reductase contents cytochromes b c1 и FeS-proteins)

complex IV (cytochrome-C- oxidase contents cytochromes а and а3 Сu)

complex V ( АТP-synthase)

electrons and protons enter the respiratory circuit in two ways

in the oxidation of NADН2 complex 1 transfers electrons and protons through FMN and FeS-protein on ubiquinone

in oxidation succinate electrons and protons are transferred on ubiquinone by complex II containing FADН2-dehydrogenase and FeS-protein

As a result in both cases the oxidized form of ubiquinone (КоQ) is restored up to ubihydrochinone (КоQН2)

Then the electrons from КоQН2 are transferred along the circuit by complex III on cytochrome C

cytochrome C transfers electrons to complex IV in which cytochrome а3 has unique properties - ability to transfer electrons on 12О2 with the for-

mation of О-2

ion which joins the protons removed from oxidized substrates through dehydrogenase and KoQ Endogenic water is formed

In the human organism as a result of cell respiration (tissue) 300 - 400 ml of water is formed for a day endogenic or metabolic water (camels in a de-

sert bears - hibernation in a den)

Complete restoration of О2 up to Н2О requires joining 4 е-

In an organism restoration of oxygen occurs stage by stage transferring 1еndash at each stage

Joining the first еndash forms superoxide anion О2

ndash

Joining two еndash forms peroxide anion О2

2ndashН2О2

Peroxide of hydrogen and superoxide radical are very toxic They are destroyed in a cell the first ndash by catalase the second ndash by superoxiddismutase

116

The organization of complexes I-V from the components of the respiratory circuit in mitochondria (scheme)

3 ADP + 3 Pi

Pro

tein

sli

pid

samp c

arb

o-

hydra

tes

of

food

АТP- synthetase

complex V complex I

NADН-dehydrogenase

FMN + FeS - protein

complex III

cytochrome c - reductase (cytochrome bc1)

and FeS - proteins

complex IV

Cytochrome C oxidase

cytochrome аа3 Cu)

КоQ

2е-+2Н

+ e-rarr

e-rarr

cytochrome

С rarre

-rarr

rarre-rarr

Ex

tern

al m

em-

bra

ne

of

mit

o-

cho

ndri

a

Inte

rnal

mem

-b

ran

e of

mit

o-

cho

ndri

a

Intercellular space

4Н2Оharr4 Н++ 4ОН

-

com

ple

x I

I

Su

ccin

ate

deh

yd

rog

enes

is

T C A

Acetyle-CoA

pyru

vat

e

acey

l-C

oA

2Н

++

2е- 4Н2Оharr4 Н

++ 4ОН

-

2Н+

4Н+

2Н

++

2е-

2Н2Оharr2 Н++ 2ОН

-

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

+ + + + + 4Н+ + + + + + + + 2Н

+ +

ОН- ОН

- ОН

-

2Н+

+12О2

12О2

2е-

Н2О

Matrix of

mitochondria

10Н+

10ОН-

10Н2О

3 А

ТP

+

hea

t NADН2

FA

DH

2

Endogenic water

(300-400 ml per day)

О2 + e- О2ˉ (superoxide anion)

О2ˉ+ e- О2

2ˉ (peroxide anion)

О2ˉ +e-+ 2H

+ H2О2 (peroxide of hydrogen)

H2О2+ О2ˉ OHˉ + OH + O2 (hydroxyle

anion and hydroxyle radical)

117

Together with electrons complexes I III and IV due to the energy of electrons

transferring of protons from mitochondrial matrix (Н + are formed at dissocia-

tion of waters) is vectorially made into intermembraneous space where the con-

centration of ions Н+ increases and on a membrane the proton potential Н +

is formed

Biological sense of electrons transport along the respira-tory circuit and transfer of protons into the intermembra-

neous space (chemiosmatic hypothesis of Mitchel -Sculachev)

Transfer of electrons along the respiratory circuit is accompanied with the

gradual releasing energy the part of which (~ 40 ) is used for the formation

of АТP and other energy dissipates as heat (heatproduction)

Energy of electrons is used for the formation of a proton gradient on the inter-

nal mitochondrial membrane The proton potential appears (an electrochemical

gradient of ions Н + Н +)

Formation of АТP (oxidative phosphorylation) entails the reverse stream of

protons from intermembraneous spaces into mitochondrial matrix however the

membrane of mitochondria is impenetrable for protons

In mitochondria only АТP- synthetase (complex V) allows to carry out the re-

verse movement of protons from intermembranal spaces in mitochondrial matrix

and the same enzyme catalyses the formation of АТP ie synthesis АТP entails

the oxidation of substrate and then coferments and cofactors of respiratory cir-

cuit with participation of oxygen Therefore this process (oxidations and phos-

phorylation of АDP with formation of АТP) has received the name of oxidative

phosphorylation

АТP- synthetase consists of two parts the proton channel (13 subunits of pro-

tein) built in the internal membrane of mitochondria and catalyzed structure

acting in mitochondrial matrix (3 α - and 3 szlig-subunits)

Cycle of formation of АТP is divided into 3 phases

Linkage with the enzyme of АDP and Р

Formation of phosphoanhydrate bond between АDP and Р with the

formation of АТP

Releasing of end-products of the reaction (АТP and waters)

Calculation of the energy educed during the transport of electrons along

the respiratory circuit

Change of free energy (G) during the transport of electrons depends only on a

difference of oxidation-reduction potentials of the donor and the acceptor of

electrons in the respiratory circuit

The general value of the energy released at transport of 2е along the respiratory

circuit can be calculated

G0 = - n F E where

118

G0 - change of free standard energy

n- the number of transferred electrons (for example we shall take 2 of them)

F ndash Faraday number = 23062 cal

mole

E ndash Difference of standard potentials of components of the respiratory cir-

cuit giving (-032 volts) and accepting (+ 082 volts) electrons

Transfer of 2 electrons is accompanied with educing

G0 = - 2 23062 [082 ndash (- 032)] = - 526

kcalmole or (237

кjulemole)

- If protons enter the intermembraneous space through complexes I III

and IV 3 molecules АТP and coefficient of phosphorylation (rela-

tion PO)= 3 are formed if protons enter only through complexes II III

and IV 2 molecules АТP and coefficient of phosphorylation (PO)

= 2 are formed where Р ndash is the quantity of the inorganic phosphate in-

cluded in 2 or 3 АТP O- atom of oxygen on which 2 e- are transferred

- The reasons of conjugation oxidation and phosphorylation (oxidative

phosphorylation) are only on 3 or 2 parts of the respiratory circuit

- On other parts the potential difference of the connected redox-systems

(energy) is insufficient for the formation of АТP in these parts energy is

releasing as heat

- Uncouples of oxidative phosphorylation promote an expenditure of

proton potential without АТP-synthetase dissociation of phosphoryla-

tion and respiration is present

- Breath increases

- Phosphorylation is suppressed

- Heat production increases

- Uncouples of respiration and phosphorylations

- thermogenins

- Free fatty acids RCOO-+ Н + (on the external part of the membrane)

RCOOH reg RCOO-+ Н + (on the internal part of the membrane)

- 24-dinitrophenol salicylates (anti-inflammatory remedies)

- Peculiarities of the formation of heat in newborns and animals born

bald and also running into hibernation (brown fat and peculiarities of

their respiratory circuit organization)

- Brown fat in newborns

- They contain more mitochondria

- They have 10 times more enzymes of respiration than phosphorylation

- Presence of thermogenins in the membrane provides dissociation of res-

piration and phosphorylation that leads to formation of a plenty of heat

warming flowing blood

Regulation of energy exchange

For a day the requirement of an organism in energy (АТP) varies

The rate of the АТP formation depends on a energy status of cells iе correla-

tion

[ATP]

[ADP] [P]

119

At rest the energy charge of a cell changes is about 09 and comes nearer to 1

unit

[АТP] + frac12 [АDP]

[АTP] [АDP] + [АMP

At use of energy (АТP) by the organism a part of АТP is hydrolized up to АDP

and Р the enrgy charge of a cell is reduced

Increase of АDP concentration automatically will increase the rate of oxidizing

phosphorylation and the formations АТP ie the respiration of mitochondria is

checked with the help of АDP This mechanism of regulation of energy ex-

change of a cell has got the name ldquothe respiratory controlrdquo - there is no res-

piration if there is no ADP in the cell

Oxidizing mode of substrate oxidation

It is catalysed with mono-and dioxygenase

monoxygenases ndashis including of 1 atom of oxygen into the oxidized

substrate and the other one into the molecule of water according to the

scheme

R RO + H2O

dioxygenases - enzymes which catalyzed the reaction - including of both atoms

of oxygen in to the oxidizing substance

R +О2 RО2

microsomal oxidation is a version of the microsomal mode (enzymes of

oxidation - cytochromes Р450 are in microsomes)

- Bile acids

- - Steroid hormones

- - Heterologous substances (drugs toxins etc)

They are oxidazed according to oxygenase mode without educing energy

H

+ O2

H

RndashН + О2 RndashОН + Н2О

2еoline

NADPН2

FAD

Fe-protein

Р450

2Н+

120

Lipid Peroxidation (LP)

Active oxygen species (НО2- peroxide radical middotО2oline - superoxide radical middotОН-

hydroxyl radical) are capable to take hydrogen away from (-СН2-) the groups of

fatty acids transforming them into (-middotСН-) groups

Such radicals easily join molecules of oxygen and become a peroxyl radical of

fatty acids

ndashmiddotСНndash + О2 ndashСНndashОndashО

middot

The radical chain reaction begins when the peroxyl radical takes a hydrogen at-

om from the other fatty acid molecule thus stimulates free radical chain re-

actions

ndashСНndashОndashОmiddot + (ndashСН2ndash) ndashСНndashОndashОН + (ndash

middotСНndash)

Nonsaturated fatty acids which turn into peroxids and hydroperoxids of li-

pids are most sensitive to Lipid Peroxidation

Products of the LP - hydroperoxids of lipids spirits aldehydes malonic alde-

hyde ketons etc

Biological significance of Lipid Peroxidation

Regulation of renovating and permeability of lipid biological mem-

branes

In phagocytic cells for destruction of the absorbed bacteria and infec-

tious material Н2О2 and a superoxide radical which initiate the LP are

used and bacteria perish

Free radical processes can completely destroy nonsaturated lipids of

biomembranes of host cells causing inevitable destruction of cells

In the membranes of cells free radical processes are limited as there are various systems of protection against active forms of oxygen (antioxidant systems) in

cells

PERIOXIDIZATION MODE

R∙H2 + O2 rarr R + H2O2

Localization in peroxysomas (about 80 of H2O2 are formed) enzymes- ox-

ydase of amino acids amines etc

Biological significance

Amino acids biogenic amines and other organic molecules are oxidized

in such a way

Thus toxic for cells of an organism hydrogen peroxide H2O2 is formed

In leukocytes H2O2 is used for neutralization of pathogenic bacteria

In cells H2O2 is neutralized with the help of enzymes (catalase [E1] peroxydase

[E2])according to the scheme

2Н2О2 2Н2О + О2

Н2О2 + R Н2О + RO

121

Protection of membranes against LP

1 Inactivization of oxygen radicals under the action of superoxide

dismutase and catalase

2 Fermentative mechanism of membrane protection against LP un-

der the action of glutathione peroxidase

3 Chemical protection of membranes against LP with the help of anti-

oxidizers (the most powerful antioxidizer is Vitamin E)

107

The role of cholesterol in peoplersquos diet (the daily requirement ˜ 15 gm ex-

ogenic and its endogenic sources cholesterol is a part of membranes the pre-

cursor of hormones bilious acids vitamins of group D)

The positive and negative action of lipids on peoplersquos health

(+)-resources of energy the sources of irreplaceable components and bi-

ologically active substances

(-) - oxidation needs more oxygen the excess leads to the disturbance of

their exchange hyperlipidemia and the development of a number of dis-

eases

The role of proteins in a diet

Importance of proteins in a diet (the source of nitrogen irreplaceable amino ac-

ids and energy)

Daily requirement (dependence on age occupation the condition of the organ-

ism) 80-100 gm assimilated proteins the half of them should be of the animal

origin

Chemical and biological significance of protein (amino-acids structure and the

degree of assimilation)

Protein-energy insufficiency and Kwashiorkor disease

Positive and negative action of protein excess on peoplersquos health

(+) the source of nitrogen irreplaceable amino acids energy

(-) it metabolize in a complicated mannerand end-products of disintegra-

tion of the protein - ammonia and urea - are rather toxic

Ethanol its part in peoplersquos diet

Consequences of alcohol abusing

ndash Metabolism of ethanol (90 in the liver)

Alcohol dehydrogenase acetaldehyde dehydrogenase

CH3 ndash CH2 ndash OH CH3 ndash C CH3 ndashC

HAD HADH2 H HAD HADH2 ОH acetaldehyde acetate

(toxic)

ACETYL-COA CO2 H2O АТP + heat

Metabolic premise of alcoholic dependence degradation of a personality and

occurrence of various diseases

CAС

О О

108

Average consumption of ethanol in the advanced countries is ˜10 of food in

caloric value

At abusing of alcoholic drinks the increase of the deficiency of entering irre-

placeable components of food into tissue (irreplaceable amino acids high fatty

acids vitamins mineral substances and celluose) occurs

Alcohol dehydrogenase and acetaldehyde dehydrogenase competing with other

dehydrogenases for NAD disturb many reactions of oxidation of substances in a

cell

The metabolism of proteins carbohydrates phospholipids (the rate of gluconeo-

genesis in the liver is reduced - arises hypoglycemia only triglycerides are in-

tensively synthesized in the liver- the fatty dystrophy of the liver develops) is

disodered

Because of protein metabolism disoder and other biologically active substances

in CNS - increases the degradation of a personality immunity and resistibility of

the organism that stimulates the development of many diseases reduce

Because of easiness of ethanol metabolism (only two enzymes are necessary for his

oxidation up to Acetyl - coA) the cells prefer an easy way of energy manufacture from this

product that conducts to accustoming cells to this product and finally to the dependence of

the organism on entering alcoholic drinks with food

General ways of the metabolism of protein fats and carbohydrates

The concept of metabolism (catabolism and anabolism) and metabolitics (substrates

and intermediate products of the exchange)

Stages and reactions of Catabolism of proteins fats and carbohydrates

PROTEINS CARBOHYDRATES LIPIDS

amino acids monosaccharides glycerin and high fatty acid

ketoacids

acetyl coA

Н2О + СО2 3NADH2

1FADH2

C A С (Citric Acid Cycle)

I

II

III

F o o d o f m a n

ATP + HEAT

Ethanol

109

Phases of catabolism and releasing of energy from nutrients

I-st phase - preparatory (in the gastroenteric tract) - transfer of food or endocellular bi-

opolymers into monomers

hydrolases in intestines or inside cells

significance of proteins fats and carbohydrates digestion in the gastroenteric

tract (hydrolysis and destruction of specific and antigenic specificity of food

components)

2-nd phase - (in cytoplasm of cells and in mitochondria) - formation of the universal

substrat of oxidation for CAC - Acetyl ndash coA from amino acids monosugars and high

fatty acids

Specific ways of disintegration of amino acids carbohydrates glycerin high

fatty acids and ethanol

Conditions are mainly anaerobic there is a presence of specific enzymes and

coferments (for example catabolism of glucose up to Acetyl - CoA requires 15

enzymes and ethanolndashonly 3 ferments)

6-7 of the energy involved in initial substrats become free thus the part of

energy is accumulated in high-energic АТP bond (substrate phosphorylation)

the other part dissipates as heat

3-rd phase - (in mitochondria) - full oxidation of acetyl-CoA in the Krebs cycle up to

СО2 and carrying protons and electrons with the help of NAD and FAD-dependent dehy-

drogenase in the respiratory circuit on О2 for the formation of АТPh (oxidative phosphory-

lation) and heat

Citric Acids Cycle (Krebs cycle) mdash Cyclic system of reactions

chemical reactions of a citric acids cycle (CAC) as a general mode of proteins

fats and carbohydrates catabolism

uml CAC begins with interaction of Acetyl- CoA and oxaloacetate with the

formation of the citric acid

uml Through a number of reactions isocitrate α-ketoglutarate succinate and

malate which are exposed to oxidation (dehydrogation) form oxaloacetate

again

uml During these reactions Acetyl - CoA molecule is oxidized up to 2 СО2

the coferments 3 NAD and 1 FAD are restored up to 3 NADH2 and

FADН2

110

HC - COOH

||

HC - COOH

fumarate

H2C - COOH

|

HO - C - COOH

|

H 2C - COOH

citrate

O

H3C - C

S - KoA

HS CoA

O = C - COOH

|

H2C - COOH

oxaloacetate

Н2О

H2C - COOH

|

C - COOH

||

HC - COOH

Cis-aconitate

СО2 NADН2 H2C - COOH

|

HC - COO H

|

HO - C - COOH

|

H

isocitrate

H2C - COOH

|

H2C- C - COO H

||

O

-ketoglutarate

NADН2

H2C - COOH

|

H2C - C ~ S KoA

||

O

succinyl CоА

GTP (АТP)

H2C - COOH

|

H2C - COOH

succinate

FADН2

ОН Н

HO - CH - COOH

|

H2C - COOH

malate

(малат)

NADН2

Н2О

Н S-CоА

СО2

Н2О

S CoA

proteins

lipids

carbohydrates

111

Biological role of the tricarbonoic acids cycle

integrative (amphibolic) ndash unites the catabolic and anabolic pathways of

carbohydrates lipids and proteins

catabolic and energetic ndash disintegration of Acetyl - CоА

- substrate phosphorylation in the tricarbonoic acids cycle (1

GTP = 1 АТP at the expense of the macroergs of succinyl-CоА)

- oxidative phosphorylation (3 NADН2-9 АТP

FADН2-2АТP only 11 АТP

- Total = 12 АТP

anabolic ndash substrats of the citric acid cycle are used for syn-

thesis of other substances

- oxaloacetate - aspartate glucose

ketoglutarate - glutamate

- succinyl-CоА - heme

Stages of proteins fats and carbohydrates anabolism

polysaccharides

proteins lipids

aminoacids monosaccharides

(glucose) fatty acids

ketoacids

pyruvate acetyle CoA

oxaloacetate

α-ketogluterate

succinate

Similarities and differences of processes of catabolism and anabolism (the place

of action enzymes coferments bio-energetics)

BIO-ENERGETICS of the CELL MECHANISMS of BIOLOGICAL OXIDATION

mdash The basic energy source for all organisms on the Earth is the sun radiation (as

a result of reactions of nuclear synthesis on the Sun)

III

II

I

g l y c e

r i n

112

mdash Photosynthesizing cells of plants catch the solar energy and use it on transfor-

mations of inorganic substances - СО2 Н2О and salts - in various rich energy

organic compounds (proteins lipids carbohydrates) Under the action of the

solar energy electrons of Н2О in the cells of plants are stimulated i е they

transfer (in the structure of proteins lipids carbohydrates) into higher energet-

ic level

mdash During disintegration of proteins fats and carbohydrates in an organism of an-

imals the return transition of electrons into lower power orbit with the for-

mation of Н2О take place which is accompanied by releasing the same quantity

of energy Hence the basic carrier of energy -electron and its source - the Sun

Laws of thermodynamics

Forms of energy (thermal chemical electric etc) and the communications exist-

ing between various forms of energy (opportunities of transformation) which

are formulated in the laws of thermodynamics

The first law of thermodynamics

sect Energy neither disappear nor arise it is only transforms from one form

into another

The second law of thermodynamics (entropy)

sect All spontaneous processes in the systems proceed only in one direction -

reduction of free energy that is not seldom accompanied by increase the

systems disorder (entropy)

The conditions necessary for preservation of homeostage of alive organisms

(constancy of the internal medium) ndash entering energy in it since processes of

disintegration are constantly present

Mathematical calculation of change of free energy

G = H ndash Т S where

G - a part of energy of the system which is spent for fulfillment of work

(kjulemole substances)

H -Change in heat contents of the system (enthalpy)

Т - absolute temperature

S - entropy change disorder of the systems

The energy enters animals organism in the form of proteins carbohydrates and

lipids catabolism of which conducts to becoming this energy free and its trans-

formation into

Energy of macroergs (АТP etc)

Electric energy

Thermal energy

Mechanical one

Energy of chemical bonds etc

113

High-energy (macroergs) and low-energy compounds of animals tissue АТP - universal macroergs in plants and animals world

macroergic compounds are called the substances having macroergic bond

macroergic bond is marked by ldquo~rdquo Energy is used for satisfaction of

energy needs of a cell

compound product of reaction -G kjulemole

phosphoenolpyruvate pyruvate + Н3РО4 619

13-bisphosphoglycerate 3-phosphoglycerate+Н3РО4 545

carbamoylphosphate carbamate + Н3РО4 515

creatinephosphate creatine + Н3РО4 431

pyrophosphate Н4Р2О7 2 Н3РО4 334

Acetyle-CoA acetate +HS-CоА 350

Succinyle-CoA succinate + HS-CoA 435

АТP (GTPUTP etc) ADP + Н3РО4 345 (~73 kcalmole)

ADP АМP + Н3РО4 363

АМP adenosine + Н3РО4 96

glycerophosphate glycerine + Н3РО4 92

glucose-6-phosphate glucose + Н3РО4 138

- Universal macroerg is ATP Its molecule serves as a part connecting among them-

selves various kinds of transformation of energy chemical mechanical electric

osmotic and other processes going with release and consumption of energy

- The reasons of release of energy at hydrolysis of macroergic bond (phospho-

anhydtate) of АТP and АDP

Redistribution of electrons on orbits

pH medium (neutral)

Significance of dissociation (АТP-4 АDP-3 АМP-2)

- Daily requirement of the adult for energy (АТP) and real presence АТP in an or-

ganism (˜65kg available 3-4g)

- Reactions n of АDP rephosphorylatio and subsequent use of АТP as an energy

source (dephosphorylation) form the cycle which repeats 25-3 thousand times per day

The diagram of the formation and use of АТP in an organism

Solar energy

plants cells (carbohy-

drates lipids proteins)

feeding of animals

Energy of

Carbohydrates lipids pro-

teins

АТP

АDP + Н3РО4

biosynthesis

Muscular reduction

Active transport of ions

through membranes (po-

tential of rest and potential

of action)

Other volatile processes

energydependent

(body temperature)

re

ph

osp

ho

ryla

tio

n

Dep

ho

sph

ory

latio

n

114

2 modes of ADP rephosphorylation

Oxidative phosphorylation

Substrate phosphorylation

The main substrates for rephosphorylation of АDP oxidation of proteins fats

and carbohydrates in tissues during their oxidation

Variants of oxidation of organic substances in animal tissues

oxidase type (dehydration and transport of electrons and protons on oxy-

gen with the formation of energy Н2О СО2) oxigenase (oxidations of a substrate by oxygen)

mechanisms of peroxide oxidation of lipids

peroxidase type (oxidation of a substrate with the formation of hydrogen

peroxide and use of the latter for oxidation of other substrates)

Oxidase type of oxidations of proteins lipids carbohydrates (cell respiration of

tissues) is the basic mode of oxidation in tissues of animals and at the same time it manu-

factures energy (АТP and heat)

Oxidase type of oxidation of substrates is provided with enzymes and coferments of

the respiratory circuit

Chemical compound of components of a respiratory circuit and their

redox-potential

Components of a respiratory circuit are collected from the set of enzymes and

polypeptides which contain a number of various oxidizing and restored

coferments and cofactors (iron copper) as a prostetic group

Е0В ndash042 ndash 032 + 004 + 007 + 023 + 025 + 029 + 055 + 082

Н NAD (FMN) Ко Q b Fe3+

c1 Fe3+

c Fe3+

a Fe3+

a3 (Cu2+

Fe3+

) 12O2

R

Н NADН2 Ко Q Н2 b Fe2+

c1 Fe2+

c Fe2+

a Fe2+

a3 (Cu+Fe

2+) Н2О

And also Fes protein ATP ATP ATP

cytochromes dehydrogenase

ndash 005

FAD

FADН2

(2)

(1)

115

The redox-potential is characterized by the energy which is released at transporting electrons from the given substance on a hydrogen electrode and is ex-

pressed in electron-volts

o The redox-potential and the function of components of the respiratory circuit depend on a chemical nature and correlation of the oxidized and

restored molecules included in their structure

o Members of oxidation-reduction lines settle down in ascending order of potentials [-032В - (+082В)]

o Components of the respiratory circuit in mitochondria are organized in complexes (the circuit is on page 15)

The respiratory circuit includes four albuminous complexes (I III IV V) built - in the internal mitochondrial membrane and two mobile systems mole-

cules - carriers - ubiquinone (КоQ) and cytochromes C Succinate dehydrogenase from cycle TCA is also considered as well as the complex of II respiratory

circuit

complex I ( NADН-dehydrogenase + FMN +FeS-proteins)

complex II ( succinate dehydrogenase + FAD +FeS-proteins)

complex III (cytochromendashC- reductase contents cytochromes b c1 и FeS-proteins)

complex IV (cytochrome-C- oxidase contents cytochromes а and а3 Сu)

complex V ( АТP-synthase)

electrons and protons enter the respiratory circuit in two ways

in the oxidation of NADН2 complex 1 transfers electrons and protons through FMN and FeS-protein on ubiquinone

in oxidation succinate electrons and protons are transferred on ubiquinone by complex II containing FADН2-dehydrogenase and FeS-protein

As a result in both cases the oxidized form of ubiquinone (КоQ) is restored up to ubihydrochinone (КоQН2)

Then the electrons from КоQН2 are transferred along the circuit by complex III on cytochrome C

cytochrome C transfers electrons to complex IV in which cytochrome а3 has unique properties - ability to transfer electrons on 12О2 with the for-

mation of О-2

ion which joins the protons removed from oxidized substrates through dehydrogenase and KoQ Endogenic water is formed

In the human organism as a result of cell respiration (tissue) 300 - 400 ml of water is formed for a day endogenic or metabolic water (camels in a de-

sert bears - hibernation in a den)

Complete restoration of О2 up to Н2О requires joining 4 е-

In an organism restoration of oxygen occurs stage by stage transferring 1еndash at each stage

Joining the first еndash forms superoxide anion О2

ndash

Joining two еndash forms peroxide anion О2

2ndashН2О2

Peroxide of hydrogen and superoxide radical are very toxic They are destroyed in a cell the first ndash by catalase the second ndash by superoxiddismutase

116

The organization of complexes I-V from the components of the respiratory circuit in mitochondria (scheme)

3 ADP + 3 Pi

Pro

tein

sli

pid

samp c

arb

o-

hydra

tes

of

food

АТP- synthetase

complex V complex I

NADН-dehydrogenase

FMN + FeS - protein

complex III

cytochrome c - reductase (cytochrome bc1)

and FeS - proteins

complex IV

Cytochrome C oxidase

cytochrome аа3 Cu)

КоQ

2е-+2Н

+ e-rarr

e-rarr

cytochrome

С rarre

-rarr

rarre-rarr

Ex

tern

al m

em-

bra

ne

of

mit

o-

cho

ndri

a

Inte

rnal

mem

-b

ran

e of

mit

o-

cho

ndri

a

Intercellular space

4Н2Оharr4 Н++ 4ОН

-

com

ple

x I

I

Su

ccin

ate

deh

yd

rog

enes

is

T C A

Acetyle-CoA

pyru

vat

e

acey

l-C

oA

2Н

++

2е- 4Н2Оharr4 Н

++ 4ОН

-

2Н+

4Н+

2Н

++

2е-

2Н2Оharr2 Н++ 2ОН

-

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

+ + + + + 4Н+ + + + + + + + 2Н

+ +

ОН- ОН

- ОН

-

2Н+

+12О2

12О2

2е-

Н2О

Matrix of

mitochondria

10Н+

10ОН-

10Н2О

3 А

ТP

+

hea

t NADН2

FA

DH

2

Endogenic water

(300-400 ml per day)

О2 + e- О2ˉ (superoxide anion)

О2ˉ+ e- О2

2ˉ (peroxide anion)

О2ˉ +e-+ 2H

+ H2О2 (peroxide of hydrogen)

H2О2+ О2ˉ OHˉ + OH + O2 (hydroxyle

anion and hydroxyle radical)

117

Together with electrons complexes I III and IV due to the energy of electrons

transferring of protons from mitochondrial matrix (Н + are formed at dissocia-

tion of waters) is vectorially made into intermembraneous space where the con-

centration of ions Н+ increases and on a membrane the proton potential Н +

is formed

Biological sense of electrons transport along the respira-tory circuit and transfer of protons into the intermembra-

neous space (chemiosmatic hypothesis of Mitchel -Sculachev)

Transfer of electrons along the respiratory circuit is accompanied with the

gradual releasing energy the part of which (~ 40 ) is used for the formation

of АТP and other energy dissipates as heat (heatproduction)

Energy of electrons is used for the formation of a proton gradient on the inter-

nal mitochondrial membrane The proton potential appears (an electrochemical

gradient of ions Н + Н +)

Formation of АТP (oxidative phosphorylation) entails the reverse stream of

protons from intermembraneous spaces into mitochondrial matrix however the

membrane of mitochondria is impenetrable for protons

In mitochondria only АТP- synthetase (complex V) allows to carry out the re-

verse movement of protons from intermembranal spaces in mitochondrial matrix

and the same enzyme catalyses the formation of АТP ie synthesis АТP entails

the oxidation of substrate and then coferments and cofactors of respiratory cir-

cuit with participation of oxygen Therefore this process (oxidations and phos-

phorylation of АDP with formation of АТP) has received the name of oxidative

phosphorylation

АТP- synthetase consists of two parts the proton channel (13 subunits of pro-

tein) built in the internal membrane of mitochondria and catalyzed structure

acting in mitochondrial matrix (3 α - and 3 szlig-subunits)

Cycle of formation of АТP is divided into 3 phases

Linkage with the enzyme of АDP and Р

Formation of phosphoanhydrate bond between АDP and Р with the

formation of АТP

Releasing of end-products of the reaction (АТP and waters)

Calculation of the energy educed during the transport of electrons along

the respiratory circuit

Change of free energy (G) during the transport of electrons depends only on a

difference of oxidation-reduction potentials of the donor and the acceptor of

electrons in the respiratory circuit

The general value of the energy released at transport of 2е along the respiratory

circuit can be calculated

G0 = - n F E where

118

G0 - change of free standard energy

n- the number of transferred electrons (for example we shall take 2 of them)

F ndash Faraday number = 23062 cal

mole

E ndash Difference of standard potentials of components of the respiratory cir-

cuit giving (-032 volts) and accepting (+ 082 volts) electrons

Transfer of 2 electrons is accompanied with educing

G0 = - 2 23062 [082 ndash (- 032)] = - 526

kcalmole or (237

кjulemole)

- If protons enter the intermembraneous space through complexes I III

and IV 3 molecules АТP and coefficient of phosphorylation (rela-

tion PO)= 3 are formed if protons enter only through complexes II III

and IV 2 molecules АТP and coefficient of phosphorylation (PO)

= 2 are formed where Р ndash is the quantity of the inorganic phosphate in-

cluded in 2 or 3 АТP O- atom of oxygen on which 2 e- are transferred

- The reasons of conjugation oxidation and phosphorylation (oxidative

phosphorylation) are only on 3 or 2 parts of the respiratory circuit

- On other parts the potential difference of the connected redox-systems

(energy) is insufficient for the formation of АТP in these parts energy is

releasing as heat

- Uncouples of oxidative phosphorylation promote an expenditure of

proton potential without АТP-synthetase dissociation of phosphoryla-

tion and respiration is present

- Breath increases

- Phosphorylation is suppressed

- Heat production increases

- Uncouples of respiration and phosphorylations

- thermogenins

- Free fatty acids RCOO-+ Н + (on the external part of the membrane)

RCOOH reg RCOO-+ Н + (on the internal part of the membrane)

- 24-dinitrophenol salicylates (anti-inflammatory remedies)

- Peculiarities of the formation of heat in newborns and animals born

bald and also running into hibernation (brown fat and peculiarities of

their respiratory circuit organization)

- Brown fat in newborns

- They contain more mitochondria

- They have 10 times more enzymes of respiration than phosphorylation

- Presence of thermogenins in the membrane provides dissociation of res-

piration and phosphorylation that leads to formation of a plenty of heat

warming flowing blood

Regulation of energy exchange

For a day the requirement of an organism in energy (АТP) varies

The rate of the АТP formation depends on a energy status of cells iе correla-

tion

[ATP]

[ADP] [P]

119

At rest the energy charge of a cell changes is about 09 and comes nearer to 1

unit

[АТP] + frac12 [АDP]

[АTP] [АDP] + [АMP

At use of energy (АТP) by the organism a part of АТP is hydrolized up to АDP

and Р the enrgy charge of a cell is reduced

Increase of АDP concentration automatically will increase the rate of oxidizing

phosphorylation and the formations АТP ie the respiration of mitochondria is

checked with the help of АDP This mechanism of regulation of energy ex-

change of a cell has got the name ldquothe respiratory controlrdquo - there is no res-

piration if there is no ADP in the cell

Oxidizing mode of substrate oxidation

It is catalysed with mono-and dioxygenase

monoxygenases ndashis including of 1 atom of oxygen into the oxidized

substrate and the other one into the molecule of water according to the

scheme

R RO + H2O

dioxygenases - enzymes which catalyzed the reaction - including of both atoms

of oxygen in to the oxidizing substance

R +О2 RО2

microsomal oxidation is a version of the microsomal mode (enzymes of

oxidation - cytochromes Р450 are in microsomes)

- Bile acids

- - Steroid hormones

- - Heterologous substances (drugs toxins etc)

They are oxidazed according to oxygenase mode without educing energy

H

+ O2

H

RndashН + О2 RndashОН + Н2О

2еoline

NADPН2

FAD

Fe-protein

Р450

2Н+

120

Lipid Peroxidation (LP)

Active oxygen species (НО2- peroxide radical middotО2oline - superoxide radical middotОН-

hydroxyl radical) are capable to take hydrogen away from (-СН2-) the groups of

fatty acids transforming them into (-middotСН-) groups

Such radicals easily join molecules of oxygen and become a peroxyl radical of

fatty acids

ndashmiddotСНndash + О2 ndashСНndashОndashО

middot

The radical chain reaction begins when the peroxyl radical takes a hydrogen at-

om from the other fatty acid molecule thus stimulates free radical chain re-

actions

ndashСНndashОndashОmiddot + (ndashСН2ndash) ndashСНndashОndashОН + (ndash

middotСНndash)

Nonsaturated fatty acids which turn into peroxids and hydroperoxids of li-

pids are most sensitive to Lipid Peroxidation

Products of the LP - hydroperoxids of lipids spirits aldehydes malonic alde-

hyde ketons etc

Biological significance of Lipid Peroxidation

Regulation of renovating and permeability of lipid biological mem-

branes

In phagocytic cells for destruction of the absorbed bacteria and infec-

tious material Н2О2 and a superoxide radical which initiate the LP are

used and bacteria perish

Free radical processes can completely destroy nonsaturated lipids of

biomembranes of host cells causing inevitable destruction of cells

In the membranes of cells free radical processes are limited as there are various systems of protection against active forms of oxygen (antioxidant systems) in

cells

PERIOXIDIZATION MODE

R∙H2 + O2 rarr R + H2O2

Localization in peroxysomas (about 80 of H2O2 are formed) enzymes- ox-

ydase of amino acids amines etc

Biological significance

Amino acids biogenic amines and other organic molecules are oxidized

in such a way

Thus toxic for cells of an organism hydrogen peroxide H2O2 is formed

In leukocytes H2O2 is used for neutralization of pathogenic bacteria

In cells H2O2 is neutralized with the help of enzymes (catalase [E1] peroxydase

[E2])according to the scheme

2Н2О2 2Н2О + О2

Н2О2 + R Н2О + RO

121

Protection of membranes against LP

1 Inactivization of oxygen radicals under the action of superoxide

dismutase and catalase

2 Fermentative mechanism of membrane protection against LP un-

der the action of glutathione peroxidase

3 Chemical protection of membranes against LP with the help of anti-

oxidizers (the most powerful antioxidizer is Vitamin E)

108

Average consumption of ethanol in the advanced countries is ˜10 of food in

caloric value

At abusing of alcoholic drinks the increase of the deficiency of entering irre-

placeable components of food into tissue (irreplaceable amino acids high fatty

acids vitamins mineral substances and celluose) occurs

Alcohol dehydrogenase and acetaldehyde dehydrogenase competing with other

dehydrogenases for NAD disturb many reactions of oxidation of substances in a

cell

The metabolism of proteins carbohydrates phospholipids (the rate of gluconeo-

genesis in the liver is reduced - arises hypoglycemia only triglycerides are in-

tensively synthesized in the liver- the fatty dystrophy of the liver develops) is

disodered

Because of protein metabolism disoder and other biologically active substances

in CNS - increases the degradation of a personality immunity and resistibility of

the organism that stimulates the development of many diseases reduce

Because of easiness of ethanol metabolism (only two enzymes are necessary for his

oxidation up to Acetyl - coA) the cells prefer an easy way of energy manufacture from this

product that conducts to accustoming cells to this product and finally to the dependence of

the organism on entering alcoholic drinks with food

General ways of the metabolism of protein fats and carbohydrates

The concept of metabolism (catabolism and anabolism) and metabolitics (substrates

and intermediate products of the exchange)

Stages and reactions of Catabolism of proteins fats and carbohydrates

PROTEINS CARBOHYDRATES LIPIDS

amino acids monosaccharides glycerin and high fatty acid

ketoacids

acetyl coA

Н2О + СО2 3NADH2

1FADH2

C A С (Citric Acid Cycle)

I

II

III

F o o d o f m a n

ATP + HEAT

Ethanol

109

Phases of catabolism and releasing of energy from nutrients

I-st phase - preparatory (in the gastroenteric tract) - transfer of food or endocellular bi-

opolymers into monomers

hydrolases in intestines or inside cells

significance of proteins fats and carbohydrates digestion in the gastroenteric

tract (hydrolysis and destruction of specific and antigenic specificity of food

components)

2-nd phase - (in cytoplasm of cells and in mitochondria) - formation of the universal

substrat of oxidation for CAC - Acetyl ndash coA from amino acids monosugars and high

fatty acids

Specific ways of disintegration of amino acids carbohydrates glycerin high

fatty acids and ethanol

Conditions are mainly anaerobic there is a presence of specific enzymes and

coferments (for example catabolism of glucose up to Acetyl - CoA requires 15

enzymes and ethanolndashonly 3 ferments)

6-7 of the energy involved in initial substrats become free thus the part of

energy is accumulated in high-energic АТP bond (substrate phosphorylation)

the other part dissipates as heat

3-rd phase - (in mitochondria) - full oxidation of acetyl-CoA in the Krebs cycle up to

СО2 and carrying protons and electrons with the help of NAD and FAD-dependent dehy-

drogenase in the respiratory circuit on О2 for the formation of АТPh (oxidative phosphory-

lation) and heat

Citric Acids Cycle (Krebs cycle) mdash Cyclic system of reactions

chemical reactions of a citric acids cycle (CAC) as a general mode of proteins

fats and carbohydrates catabolism

uml CAC begins with interaction of Acetyl- CoA and oxaloacetate with the

formation of the citric acid

uml Through a number of reactions isocitrate α-ketoglutarate succinate and

malate which are exposed to oxidation (dehydrogation) form oxaloacetate

again

uml During these reactions Acetyl - CoA molecule is oxidized up to 2 СО2

the coferments 3 NAD and 1 FAD are restored up to 3 NADH2 and

FADН2

110

HC - COOH

||

HC - COOH

fumarate

H2C - COOH

|

HO - C - COOH

|

H 2C - COOH

citrate

O

H3C - C

S - KoA

HS CoA

O = C - COOH

|

H2C - COOH

oxaloacetate

Н2О

H2C - COOH

|

C - COOH

||

HC - COOH

Cis-aconitate

СО2 NADН2 H2C - COOH

|

HC - COO H

|

HO - C - COOH

|

H

isocitrate

H2C - COOH

|

H2C- C - COO H

||

O

-ketoglutarate

NADН2

H2C - COOH

|

H2C - C ~ S KoA

||

O

succinyl CоА

GTP (АТP)

H2C - COOH

|

H2C - COOH

succinate

FADН2

ОН Н

HO - CH - COOH

|

H2C - COOH

malate

(малат)

NADН2

Н2О

Н S-CоА

СО2

Н2О

S CoA

proteins

lipids

carbohydrates

111

Biological role of the tricarbonoic acids cycle

integrative (amphibolic) ndash unites the catabolic and anabolic pathways of

carbohydrates lipids and proteins

catabolic and energetic ndash disintegration of Acetyl - CоА

- substrate phosphorylation in the tricarbonoic acids cycle (1

GTP = 1 АТP at the expense of the macroergs of succinyl-CоА)

- oxidative phosphorylation (3 NADН2-9 АТP

FADН2-2АТP only 11 АТP

- Total = 12 АТP

anabolic ndash substrats of the citric acid cycle are used for syn-

thesis of other substances

- oxaloacetate - aspartate glucose

ketoglutarate - glutamate

- succinyl-CоА - heme

Stages of proteins fats and carbohydrates anabolism

polysaccharides

proteins lipids

aminoacids monosaccharides

(glucose) fatty acids

ketoacids

pyruvate acetyle CoA

oxaloacetate

α-ketogluterate

succinate

Similarities and differences of processes of catabolism and anabolism (the place

of action enzymes coferments bio-energetics)

BIO-ENERGETICS of the CELL MECHANISMS of BIOLOGICAL OXIDATION

mdash The basic energy source for all organisms on the Earth is the sun radiation (as

a result of reactions of nuclear synthesis on the Sun)

III

II

I

g l y c e

r i n

112

mdash Photosynthesizing cells of plants catch the solar energy and use it on transfor-

mations of inorganic substances - СО2 Н2О and salts - in various rich energy

organic compounds (proteins lipids carbohydrates) Under the action of the

solar energy electrons of Н2О in the cells of plants are stimulated i е they

transfer (in the structure of proteins lipids carbohydrates) into higher energet-

ic level

mdash During disintegration of proteins fats and carbohydrates in an organism of an-

imals the return transition of electrons into lower power orbit with the for-

mation of Н2О take place which is accompanied by releasing the same quantity

of energy Hence the basic carrier of energy -electron and its source - the Sun

Laws of thermodynamics

Forms of energy (thermal chemical electric etc) and the communications exist-

ing between various forms of energy (opportunities of transformation) which

are formulated in the laws of thermodynamics

The first law of thermodynamics

sect Energy neither disappear nor arise it is only transforms from one form

into another

The second law of thermodynamics (entropy)

sect All spontaneous processes in the systems proceed only in one direction -

reduction of free energy that is not seldom accompanied by increase the

systems disorder (entropy)

The conditions necessary for preservation of homeostage of alive organisms

(constancy of the internal medium) ndash entering energy in it since processes of

disintegration are constantly present

Mathematical calculation of change of free energy

G = H ndash Т S where

G - a part of energy of the system which is spent for fulfillment of work

(kjulemole substances)

H -Change in heat contents of the system (enthalpy)

Т - absolute temperature

S - entropy change disorder of the systems

The energy enters animals organism in the form of proteins carbohydrates and

lipids catabolism of which conducts to becoming this energy free and its trans-

formation into

Energy of macroergs (АТP etc)

Electric energy

Thermal energy

Mechanical one

Energy of chemical bonds etc

113

High-energy (macroergs) and low-energy compounds of animals tissue АТP - universal macroergs in plants and animals world

macroergic compounds are called the substances having macroergic bond

macroergic bond is marked by ldquo~rdquo Energy is used for satisfaction of

energy needs of a cell

compound product of reaction -G kjulemole

phosphoenolpyruvate pyruvate + Н3РО4 619

13-bisphosphoglycerate 3-phosphoglycerate+Н3РО4 545

carbamoylphosphate carbamate + Н3РО4 515

creatinephosphate creatine + Н3РО4 431

pyrophosphate Н4Р2О7 2 Н3РО4 334

Acetyle-CoA acetate +HS-CоА 350

Succinyle-CoA succinate + HS-CoA 435

АТP (GTPUTP etc) ADP + Н3РО4 345 (~73 kcalmole)

ADP АМP + Н3РО4 363

АМP adenosine + Н3РО4 96

glycerophosphate glycerine + Н3РО4 92

glucose-6-phosphate glucose + Н3РО4 138

- Universal macroerg is ATP Its molecule serves as a part connecting among them-

selves various kinds of transformation of energy chemical mechanical electric

osmotic and other processes going with release and consumption of energy

- The reasons of release of energy at hydrolysis of macroergic bond (phospho-

anhydtate) of АТP and АDP

Redistribution of electrons on orbits

pH medium (neutral)

Significance of dissociation (АТP-4 АDP-3 АМP-2)

- Daily requirement of the adult for energy (АТP) and real presence АТP in an or-

ganism (˜65kg available 3-4g)

- Reactions n of АDP rephosphorylatio and subsequent use of АТP as an energy

source (dephosphorylation) form the cycle which repeats 25-3 thousand times per day

The diagram of the formation and use of АТP in an organism

Solar energy

plants cells (carbohy-

drates lipids proteins)

feeding of animals

Energy of

Carbohydrates lipids pro-

teins

АТP

АDP + Н3РО4

biosynthesis

Muscular reduction

Active transport of ions

through membranes (po-

tential of rest and potential

of action)

Other volatile processes

energydependent

(body temperature)

re

ph

osp

ho

ryla

tio

n

Dep

ho

sph

ory

latio

n

114

2 modes of ADP rephosphorylation

Oxidative phosphorylation

Substrate phosphorylation

The main substrates for rephosphorylation of АDP oxidation of proteins fats

and carbohydrates in tissues during their oxidation

Variants of oxidation of organic substances in animal tissues

oxidase type (dehydration and transport of electrons and protons on oxy-

gen with the formation of energy Н2О СО2) oxigenase (oxidations of a substrate by oxygen)

mechanisms of peroxide oxidation of lipids

peroxidase type (oxidation of a substrate with the formation of hydrogen

peroxide and use of the latter for oxidation of other substrates)

Oxidase type of oxidations of proteins lipids carbohydrates (cell respiration of

tissues) is the basic mode of oxidation in tissues of animals and at the same time it manu-

factures energy (АТP and heat)

Oxidase type of oxidation of substrates is provided with enzymes and coferments of

the respiratory circuit

Chemical compound of components of a respiratory circuit and their

redox-potential

Components of a respiratory circuit are collected from the set of enzymes and

polypeptides which contain a number of various oxidizing and restored

coferments and cofactors (iron copper) as a prostetic group

Е0В ndash042 ndash 032 + 004 + 007 + 023 + 025 + 029 + 055 + 082

Н NAD (FMN) Ко Q b Fe3+

c1 Fe3+

c Fe3+

a Fe3+

a3 (Cu2+

Fe3+

) 12O2

R

Н NADН2 Ко Q Н2 b Fe2+

c1 Fe2+

c Fe2+

a Fe2+

a3 (Cu+Fe

2+) Н2О

And also Fes protein ATP ATP ATP

cytochromes dehydrogenase

ndash 005

FAD

FADН2

(2)

(1)

115

The redox-potential is characterized by the energy which is released at transporting electrons from the given substance on a hydrogen electrode and is ex-

pressed in electron-volts

o The redox-potential and the function of components of the respiratory circuit depend on a chemical nature and correlation of the oxidized and

restored molecules included in their structure

o Members of oxidation-reduction lines settle down in ascending order of potentials [-032В - (+082В)]

o Components of the respiratory circuit in mitochondria are organized in complexes (the circuit is on page 15)

The respiratory circuit includes four albuminous complexes (I III IV V) built - in the internal mitochondrial membrane and two mobile systems mole-

cules - carriers - ubiquinone (КоQ) and cytochromes C Succinate dehydrogenase from cycle TCA is also considered as well as the complex of II respiratory

circuit

complex I ( NADН-dehydrogenase + FMN +FeS-proteins)

complex II ( succinate dehydrogenase + FAD +FeS-proteins)

complex III (cytochromendashC- reductase contents cytochromes b c1 и FeS-proteins)

complex IV (cytochrome-C- oxidase contents cytochromes а and а3 Сu)

complex V ( АТP-synthase)

electrons and protons enter the respiratory circuit in two ways

in the oxidation of NADН2 complex 1 transfers electrons and protons through FMN and FeS-protein on ubiquinone

in oxidation succinate electrons and protons are transferred on ubiquinone by complex II containing FADН2-dehydrogenase and FeS-protein

As a result in both cases the oxidized form of ubiquinone (КоQ) is restored up to ubihydrochinone (КоQН2)

Then the electrons from КоQН2 are transferred along the circuit by complex III on cytochrome C

cytochrome C transfers electrons to complex IV in which cytochrome а3 has unique properties - ability to transfer electrons on 12О2 with the for-

mation of О-2

ion which joins the protons removed from oxidized substrates through dehydrogenase and KoQ Endogenic water is formed

In the human organism as a result of cell respiration (tissue) 300 - 400 ml of water is formed for a day endogenic or metabolic water (camels in a de-

sert bears - hibernation in a den)

Complete restoration of О2 up to Н2О requires joining 4 е-

In an organism restoration of oxygen occurs stage by stage transferring 1еndash at each stage

Joining the first еndash forms superoxide anion О2

ndash

Joining two еndash forms peroxide anion О2

2ndashН2О2

Peroxide of hydrogen and superoxide radical are very toxic They are destroyed in a cell the first ndash by catalase the second ndash by superoxiddismutase

116

The organization of complexes I-V from the components of the respiratory circuit in mitochondria (scheme)

3 ADP + 3 Pi

Pro

tein

sli

pid

samp c

arb

o-

hydra

tes

of

food

АТP- synthetase

complex V complex I

NADН-dehydrogenase

FMN + FeS - protein

complex III

cytochrome c - reductase (cytochrome bc1)

and FeS - proteins

complex IV

Cytochrome C oxidase

cytochrome аа3 Cu)

КоQ

2е-+2Н

+ e-rarr

e-rarr

cytochrome

С rarre

-rarr

rarre-rarr

Ex

tern

al m

em-

bra

ne

of

mit

o-

cho

ndri

a

Inte

rnal

mem

-b

ran

e of

mit

o-

cho

ndri

a

Intercellular space

4Н2Оharr4 Н++ 4ОН

-

com

ple

x I

I

Su

ccin

ate

deh

yd

rog

enes

is

T C A

Acetyle-CoA

pyru

vat

e

acey

l-C

oA

2Н

++

2е- 4Н2Оharr4 Н

++ 4ОН

-

2Н+

4Н+

2Н

++

2е-

2Н2Оharr2 Н++ 2ОН

-

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

+ + + + + 4Н+ + + + + + + + 2Н

+ +

ОН- ОН

- ОН

-

2Н+

+12О2

12О2

2е-

Н2О

Matrix of

mitochondria

10Н+

10ОН-

10Н2О

3 А

ТP

+

hea

t NADН2

FA

DH

2

Endogenic water

(300-400 ml per day)

О2 + e- О2ˉ (superoxide anion)

О2ˉ+ e- О2

2ˉ (peroxide anion)

О2ˉ +e-+ 2H

+ H2О2 (peroxide of hydrogen)

H2О2+ О2ˉ OHˉ + OH + O2 (hydroxyle

anion and hydroxyle radical)

117

Together with electrons complexes I III and IV due to the energy of electrons

transferring of protons from mitochondrial matrix (Н + are formed at dissocia-

tion of waters) is vectorially made into intermembraneous space where the con-

centration of ions Н+ increases and on a membrane the proton potential Н +

is formed

Biological sense of electrons transport along the respira-tory circuit and transfer of protons into the intermembra-

neous space (chemiosmatic hypothesis of Mitchel -Sculachev)

Transfer of electrons along the respiratory circuit is accompanied with the

gradual releasing energy the part of which (~ 40 ) is used for the formation

of АТP and other energy dissipates as heat (heatproduction)

Energy of electrons is used for the formation of a proton gradient on the inter-

nal mitochondrial membrane The proton potential appears (an electrochemical

gradient of ions Н + Н +)

Formation of АТP (oxidative phosphorylation) entails the reverse stream of

protons from intermembraneous spaces into mitochondrial matrix however the

membrane of mitochondria is impenetrable for protons

In mitochondria only АТP- synthetase (complex V) allows to carry out the re-

verse movement of protons from intermembranal spaces in mitochondrial matrix

and the same enzyme catalyses the formation of АТP ie synthesis АТP entails

the oxidation of substrate and then coferments and cofactors of respiratory cir-

cuit with participation of oxygen Therefore this process (oxidations and phos-

phorylation of АDP with formation of АТP) has received the name of oxidative

phosphorylation

АТP- synthetase consists of two parts the proton channel (13 subunits of pro-

tein) built in the internal membrane of mitochondria and catalyzed structure

acting in mitochondrial matrix (3 α - and 3 szlig-subunits)

Cycle of formation of АТP is divided into 3 phases

Linkage with the enzyme of АDP and Р

Formation of phosphoanhydrate bond between АDP and Р with the

formation of АТP

Releasing of end-products of the reaction (АТP and waters)

Calculation of the energy educed during the transport of electrons along

the respiratory circuit

Change of free energy (G) during the transport of electrons depends only on a

difference of oxidation-reduction potentials of the donor and the acceptor of

electrons in the respiratory circuit

The general value of the energy released at transport of 2е along the respiratory

circuit can be calculated

G0 = - n F E where

118

G0 - change of free standard energy

n- the number of transferred electrons (for example we shall take 2 of them)

F ndash Faraday number = 23062 cal

mole

E ndash Difference of standard potentials of components of the respiratory cir-

cuit giving (-032 volts) and accepting (+ 082 volts) electrons

Transfer of 2 electrons is accompanied with educing

G0 = - 2 23062 [082 ndash (- 032)] = - 526

kcalmole or (237

кjulemole)

- If protons enter the intermembraneous space through complexes I III

and IV 3 molecules АТP and coefficient of phosphorylation (rela-

tion PO)= 3 are formed if protons enter only through complexes II III

and IV 2 molecules АТP and coefficient of phosphorylation (PO)

= 2 are formed where Р ndash is the quantity of the inorganic phosphate in-

cluded in 2 or 3 АТP O- atom of oxygen on which 2 e- are transferred

- The reasons of conjugation oxidation and phosphorylation (oxidative

phosphorylation) are only on 3 or 2 parts of the respiratory circuit

- On other parts the potential difference of the connected redox-systems

(energy) is insufficient for the formation of АТP in these parts energy is

releasing as heat

- Uncouples of oxidative phosphorylation promote an expenditure of

proton potential without АТP-synthetase dissociation of phosphoryla-

tion and respiration is present

- Breath increases

- Phosphorylation is suppressed

- Heat production increases

- Uncouples of respiration and phosphorylations

- thermogenins

- Free fatty acids RCOO-+ Н + (on the external part of the membrane)

RCOOH reg RCOO-+ Н + (on the internal part of the membrane)

- 24-dinitrophenol salicylates (anti-inflammatory remedies)

- Peculiarities of the formation of heat in newborns and animals born

bald and also running into hibernation (brown fat and peculiarities of

their respiratory circuit organization)

- Brown fat in newborns

- They contain more mitochondria

- They have 10 times more enzymes of respiration than phosphorylation

- Presence of thermogenins in the membrane provides dissociation of res-

piration and phosphorylation that leads to formation of a plenty of heat

warming flowing blood

Regulation of energy exchange

For a day the requirement of an organism in energy (АТP) varies

The rate of the АТP formation depends on a energy status of cells iе correla-

tion

[ATP]

[ADP] [P]

119

At rest the energy charge of a cell changes is about 09 and comes nearer to 1

unit

[АТP] + frac12 [АDP]

[АTP] [АDP] + [АMP

At use of energy (АТP) by the organism a part of АТP is hydrolized up to АDP

and Р the enrgy charge of a cell is reduced

Increase of АDP concentration automatically will increase the rate of oxidizing

phosphorylation and the formations АТP ie the respiration of mitochondria is

checked with the help of АDP This mechanism of regulation of energy ex-

change of a cell has got the name ldquothe respiratory controlrdquo - there is no res-

piration if there is no ADP in the cell

Oxidizing mode of substrate oxidation

It is catalysed with mono-and dioxygenase

monoxygenases ndashis including of 1 atom of oxygen into the oxidized

substrate and the other one into the molecule of water according to the

scheme

R RO + H2O

dioxygenases - enzymes which catalyzed the reaction - including of both atoms

of oxygen in to the oxidizing substance

R +О2 RО2

microsomal oxidation is a version of the microsomal mode (enzymes of

oxidation - cytochromes Р450 are in microsomes)

- Bile acids

- - Steroid hormones

- - Heterologous substances (drugs toxins etc)

They are oxidazed according to oxygenase mode without educing energy

H

+ O2

H

RndashН + О2 RndashОН + Н2О

2еoline

NADPН2

FAD

Fe-protein

Р450

2Н+

120

Lipid Peroxidation (LP)

Active oxygen species (НО2- peroxide radical middotО2oline - superoxide radical middotОН-

hydroxyl radical) are capable to take hydrogen away from (-СН2-) the groups of

fatty acids transforming them into (-middotСН-) groups

Such radicals easily join molecules of oxygen and become a peroxyl radical of

fatty acids

ndashmiddotСНndash + О2 ndashСНndashОndashО

middot

The radical chain reaction begins when the peroxyl radical takes a hydrogen at-

om from the other fatty acid molecule thus stimulates free radical chain re-

actions

ndashСНndashОndashОmiddot + (ndashСН2ndash) ndashСНndashОndashОН + (ndash

middotСНndash)

Nonsaturated fatty acids which turn into peroxids and hydroperoxids of li-

pids are most sensitive to Lipid Peroxidation

Products of the LP - hydroperoxids of lipids spirits aldehydes malonic alde-

hyde ketons etc

Biological significance of Lipid Peroxidation

Regulation of renovating and permeability of lipid biological mem-

branes

In phagocytic cells for destruction of the absorbed bacteria and infec-

tious material Н2О2 and a superoxide radical which initiate the LP are

used and bacteria perish

Free radical processes can completely destroy nonsaturated lipids of

biomembranes of host cells causing inevitable destruction of cells

In the membranes of cells free radical processes are limited as there are various systems of protection against active forms of oxygen (antioxidant systems) in

cells

PERIOXIDIZATION MODE

R∙H2 + O2 rarr R + H2O2

Localization in peroxysomas (about 80 of H2O2 are formed) enzymes- ox-

ydase of amino acids amines etc

Biological significance

Amino acids biogenic amines and other organic molecules are oxidized

in such a way

Thus toxic for cells of an organism hydrogen peroxide H2O2 is formed

In leukocytes H2O2 is used for neutralization of pathogenic bacteria

In cells H2O2 is neutralized with the help of enzymes (catalase [E1] peroxydase

[E2])according to the scheme

2Н2О2 2Н2О + О2

Н2О2 + R Н2О + RO

121

Protection of membranes against LP

1 Inactivization of oxygen radicals under the action of superoxide

dismutase and catalase

2 Fermentative mechanism of membrane protection against LP un-

der the action of glutathione peroxidase

3 Chemical protection of membranes against LP with the help of anti-

oxidizers (the most powerful antioxidizer is Vitamin E)

109

Phases of catabolism and releasing of energy from nutrients

I-st phase - preparatory (in the gastroenteric tract) - transfer of food or endocellular bi-

opolymers into monomers

hydrolases in intestines or inside cells

significance of proteins fats and carbohydrates digestion in the gastroenteric

tract (hydrolysis and destruction of specific and antigenic specificity of food

components)

2-nd phase - (in cytoplasm of cells and in mitochondria) - formation of the universal

substrat of oxidation for CAC - Acetyl ndash coA from amino acids monosugars and high

fatty acids

Specific ways of disintegration of amino acids carbohydrates glycerin high

fatty acids and ethanol

Conditions are mainly anaerobic there is a presence of specific enzymes and

coferments (for example catabolism of glucose up to Acetyl - CoA requires 15

enzymes and ethanolndashonly 3 ferments)

6-7 of the energy involved in initial substrats become free thus the part of

energy is accumulated in high-energic АТP bond (substrate phosphorylation)

the other part dissipates as heat

3-rd phase - (in mitochondria) - full oxidation of acetyl-CoA in the Krebs cycle up to

СО2 and carrying protons and electrons with the help of NAD and FAD-dependent dehy-

drogenase in the respiratory circuit on О2 for the formation of АТPh (oxidative phosphory-

lation) and heat

Citric Acids Cycle (Krebs cycle) mdash Cyclic system of reactions

chemical reactions of a citric acids cycle (CAC) as a general mode of proteins

fats and carbohydrates catabolism

uml CAC begins with interaction of Acetyl- CoA and oxaloacetate with the

formation of the citric acid

uml Through a number of reactions isocitrate α-ketoglutarate succinate and

malate which are exposed to oxidation (dehydrogation) form oxaloacetate

again

uml During these reactions Acetyl - CoA molecule is oxidized up to 2 СО2

the coferments 3 NAD and 1 FAD are restored up to 3 NADH2 and

FADН2

110

HC - COOH

||

HC - COOH

fumarate

H2C - COOH

|

HO - C - COOH

|

H 2C - COOH

citrate

O

H3C - C

S - KoA

HS CoA

O = C - COOH

|

H2C - COOH

oxaloacetate

Н2О

H2C - COOH

|

C - COOH

||

HC - COOH

Cis-aconitate

СО2 NADН2 H2C - COOH

|

HC - COO H

|

HO - C - COOH

|

H

isocitrate

H2C - COOH

|

H2C- C - COO H

||

O

-ketoglutarate

NADН2

H2C - COOH

|

H2C - C ~ S KoA

||

O

succinyl CоА

GTP (АТP)

H2C - COOH

|

H2C - COOH

succinate

FADН2

ОН Н

HO - CH - COOH

|

H2C - COOH

malate

(малат)

NADН2

Н2О

Н S-CоА

СО2

Н2О

S CoA

proteins

lipids

carbohydrates

111

Biological role of the tricarbonoic acids cycle

integrative (amphibolic) ndash unites the catabolic and anabolic pathways of

carbohydrates lipids and proteins

catabolic and energetic ndash disintegration of Acetyl - CоА

- substrate phosphorylation in the tricarbonoic acids cycle (1

GTP = 1 АТP at the expense of the macroergs of succinyl-CоА)

- oxidative phosphorylation (3 NADН2-9 АТP

FADН2-2АТP only 11 АТP

- Total = 12 АТP

anabolic ndash substrats of the citric acid cycle are used for syn-

thesis of other substances

- oxaloacetate - aspartate glucose

ketoglutarate - glutamate

- succinyl-CоА - heme

Stages of proteins fats and carbohydrates anabolism

polysaccharides

proteins lipids

aminoacids monosaccharides

(glucose) fatty acids

ketoacids

pyruvate acetyle CoA

oxaloacetate

α-ketogluterate

succinate

Similarities and differences of processes of catabolism and anabolism (the place

of action enzymes coferments bio-energetics)

BIO-ENERGETICS of the CELL MECHANISMS of BIOLOGICAL OXIDATION

mdash The basic energy source for all organisms on the Earth is the sun radiation (as

a result of reactions of nuclear synthesis on the Sun)

III

II

I

g l y c e

r i n

112

mdash Photosynthesizing cells of plants catch the solar energy and use it on transfor-

mations of inorganic substances - СО2 Н2О and salts - in various rich energy

organic compounds (proteins lipids carbohydrates) Under the action of the

solar energy electrons of Н2О in the cells of plants are stimulated i е they

transfer (in the structure of proteins lipids carbohydrates) into higher energet-

ic level

mdash During disintegration of proteins fats and carbohydrates in an organism of an-

imals the return transition of electrons into lower power orbit with the for-

mation of Н2О take place which is accompanied by releasing the same quantity

of energy Hence the basic carrier of energy -electron and its source - the Sun

Laws of thermodynamics

Forms of energy (thermal chemical electric etc) and the communications exist-

ing between various forms of energy (opportunities of transformation) which

are formulated in the laws of thermodynamics

The first law of thermodynamics

sect Energy neither disappear nor arise it is only transforms from one form

into another

The second law of thermodynamics (entropy)

sect All spontaneous processes in the systems proceed only in one direction -

reduction of free energy that is not seldom accompanied by increase the

systems disorder (entropy)

The conditions necessary for preservation of homeostage of alive organisms

(constancy of the internal medium) ndash entering energy in it since processes of

disintegration are constantly present

Mathematical calculation of change of free energy

G = H ndash Т S where

G - a part of energy of the system which is spent for fulfillment of work

(kjulemole substances)

H -Change in heat contents of the system (enthalpy)

Т - absolute temperature

S - entropy change disorder of the systems

The energy enters animals organism in the form of proteins carbohydrates and

lipids catabolism of which conducts to becoming this energy free and its trans-

formation into

Energy of macroergs (АТP etc)

Electric energy

Thermal energy

Mechanical one

Energy of chemical bonds etc

113

High-energy (macroergs) and low-energy compounds of animals tissue АТP - universal macroergs in plants and animals world

macroergic compounds are called the substances having macroergic bond

macroergic bond is marked by ldquo~rdquo Energy is used for satisfaction of

energy needs of a cell

compound product of reaction -G kjulemole

phosphoenolpyruvate pyruvate + Н3РО4 619

13-bisphosphoglycerate 3-phosphoglycerate+Н3РО4 545

carbamoylphosphate carbamate + Н3РО4 515

creatinephosphate creatine + Н3РО4 431

pyrophosphate Н4Р2О7 2 Н3РО4 334

Acetyle-CoA acetate +HS-CоА 350

Succinyle-CoA succinate + HS-CoA 435

АТP (GTPUTP etc) ADP + Н3РО4 345 (~73 kcalmole)

ADP АМP + Н3РО4 363

АМP adenosine + Н3РО4 96

glycerophosphate glycerine + Н3РО4 92

glucose-6-phosphate glucose + Н3РО4 138

- Universal macroerg is ATP Its molecule serves as a part connecting among them-

selves various kinds of transformation of energy chemical mechanical electric

osmotic and other processes going with release and consumption of energy

- The reasons of release of energy at hydrolysis of macroergic bond (phospho-

anhydtate) of АТP and АDP

Redistribution of electrons on orbits

pH medium (neutral)

Significance of dissociation (АТP-4 АDP-3 АМP-2)

- Daily requirement of the adult for energy (АТP) and real presence АТP in an or-

ganism (˜65kg available 3-4g)

- Reactions n of АDP rephosphorylatio and subsequent use of АТP as an energy

source (dephosphorylation) form the cycle which repeats 25-3 thousand times per day

The diagram of the formation and use of АТP in an organism

Solar energy

plants cells (carbohy-

drates lipids proteins)

feeding of animals

Energy of

Carbohydrates lipids pro-

teins

АТP

АDP + Н3РО4

biosynthesis

Muscular reduction

Active transport of ions

through membranes (po-

tential of rest and potential

of action)

Other volatile processes

energydependent

(body temperature)

re

ph

osp

ho

ryla

tio

n

Dep

ho

sph

ory

latio

n

114

2 modes of ADP rephosphorylation

Oxidative phosphorylation

Substrate phosphorylation

The main substrates for rephosphorylation of АDP oxidation of proteins fats

and carbohydrates in tissues during their oxidation

Variants of oxidation of organic substances in animal tissues

oxidase type (dehydration and transport of electrons and protons on oxy-

gen with the formation of energy Н2О СО2) oxigenase (oxidations of a substrate by oxygen)

mechanisms of peroxide oxidation of lipids

peroxidase type (oxidation of a substrate with the formation of hydrogen

peroxide and use of the latter for oxidation of other substrates)

Oxidase type of oxidations of proteins lipids carbohydrates (cell respiration of

tissues) is the basic mode of oxidation in tissues of animals and at the same time it manu-

factures energy (АТP and heat)

Oxidase type of oxidation of substrates is provided with enzymes and coferments of

the respiratory circuit

Chemical compound of components of a respiratory circuit and their

redox-potential

Components of a respiratory circuit are collected from the set of enzymes and

polypeptides which contain a number of various oxidizing and restored

coferments and cofactors (iron copper) as a prostetic group

Е0В ndash042 ndash 032 + 004 + 007 + 023 + 025 + 029 + 055 + 082

Н NAD (FMN) Ко Q b Fe3+

c1 Fe3+

c Fe3+

a Fe3+

a3 (Cu2+

Fe3+

) 12O2

R

Н NADН2 Ко Q Н2 b Fe2+

c1 Fe2+

c Fe2+

a Fe2+

a3 (Cu+Fe

2+) Н2О

And also Fes protein ATP ATP ATP

cytochromes dehydrogenase

ndash 005

FAD

FADН2

(2)

(1)

115

The redox-potential is characterized by the energy which is released at transporting electrons from the given substance on a hydrogen electrode and is ex-

pressed in electron-volts

o The redox-potential and the function of components of the respiratory circuit depend on a chemical nature and correlation of the oxidized and

restored molecules included in their structure

o Members of oxidation-reduction lines settle down in ascending order of potentials [-032В - (+082В)]

o Components of the respiratory circuit in mitochondria are organized in complexes (the circuit is on page 15)

The respiratory circuit includes four albuminous complexes (I III IV V) built - in the internal mitochondrial membrane and two mobile systems mole-

cules - carriers - ubiquinone (КоQ) and cytochromes C Succinate dehydrogenase from cycle TCA is also considered as well as the complex of II respiratory

circuit

complex I ( NADН-dehydrogenase + FMN +FeS-proteins)

complex II ( succinate dehydrogenase + FAD +FeS-proteins)

complex III (cytochromendashC- reductase contents cytochromes b c1 и FeS-proteins)

complex IV (cytochrome-C- oxidase contents cytochromes а and а3 Сu)

complex V ( АТP-synthase)

electrons and protons enter the respiratory circuit in two ways

in the oxidation of NADН2 complex 1 transfers electrons and protons through FMN and FeS-protein on ubiquinone

in oxidation succinate electrons and protons are transferred on ubiquinone by complex II containing FADН2-dehydrogenase and FeS-protein

As a result in both cases the oxidized form of ubiquinone (КоQ) is restored up to ubihydrochinone (КоQН2)

Then the electrons from КоQН2 are transferred along the circuit by complex III on cytochrome C

cytochrome C transfers electrons to complex IV in which cytochrome а3 has unique properties - ability to transfer electrons on 12О2 with the for-

mation of О-2

ion which joins the protons removed from oxidized substrates through dehydrogenase and KoQ Endogenic water is formed

In the human organism as a result of cell respiration (tissue) 300 - 400 ml of water is formed for a day endogenic or metabolic water (camels in a de-

sert bears - hibernation in a den)

Complete restoration of О2 up to Н2О requires joining 4 е-

In an organism restoration of oxygen occurs stage by stage transferring 1еndash at each stage

Joining the first еndash forms superoxide anion О2

ndash

Joining two еndash forms peroxide anion О2

2ndashН2О2

Peroxide of hydrogen and superoxide radical are very toxic They are destroyed in a cell the first ndash by catalase the second ndash by superoxiddismutase

116

The organization of complexes I-V from the components of the respiratory circuit in mitochondria (scheme)

3 ADP + 3 Pi

Pro

tein

sli

pid

samp c

arb

o-

hydra

tes

of

food

АТP- synthetase

complex V complex I

NADН-dehydrogenase

FMN + FeS - protein

complex III

cytochrome c - reductase (cytochrome bc1)

and FeS - proteins

complex IV

Cytochrome C oxidase

cytochrome аа3 Cu)

КоQ

2е-+2Н

+ e-rarr

e-rarr

cytochrome

С rarre

-rarr

rarre-rarr

Ex

tern

al m

em-

bra

ne

of

mit

o-

cho

ndri

a

Inte

rnal

mem

-b

ran

e of

mit

o-

cho

ndri

a

Intercellular space

4Н2Оharr4 Н++ 4ОН

-

com

ple

x I

I

Su

ccin

ate

deh

yd

rog

enes

is

T C A

Acetyle-CoA

pyru

vat

e

acey

l-C

oA

2Н

++

2е- 4Н2Оharr4 Н

++ 4ОН

-

2Н+

4Н+

2Н

++

2е-

2Н2Оharr2 Н++ 2ОН

-

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

+ + + + + 4Н+ + + + + + + + 2Н

+ +

ОН- ОН

- ОН

-

2Н+

+12О2

12О2

2е-

Н2О

Matrix of

mitochondria

10Н+

10ОН-

10Н2О

3 А

ТP

+

hea

t NADН2

FA

DH

2

Endogenic water

(300-400 ml per day)

О2 + e- О2ˉ (superoxide anion)

О2ˉ+ e- О2

2ˉ (peroxide anion)

О2ˉ +e-+ 2H

+ H2О2 (peroxide of hydrogen)

H2О2+ О2ˉ OHˉ + OH + O2 (hydroxyle

anion and hydroxyle radical)

117

Together with electrons complexes I III and IV due to the energy of electrons

transferring of protons from mitochondrial matrix (Н + are formed at dissocia-

tion of waters) is vectorially made into intermembraneous space where the con-

centration of ions Н+ increases and on a membrane the proton potential Н +

is formed

Biological sense of electrons transport along the respira-tory circuit and transfer of protons into the intermembra-

neous space (chemiosmatic hypothesis of Mitchel -Sculachev)

Transfer of electrons along the respiratory circuit is accompanied with the

gradual releasing energy the part of which (~ 40 ) is used for the formation

of АТP and other energy dissipates as heat (heatproduction)

Energy of electrons is used for the formation of a proton gradient on the inter-

nal mitochondrial membrane The proton potential appears (an electrochemical

gradient of ions Н + Н +)

Formation of АТP (oxidative phosphorylation) entails the reverse stream of

protons from intermembraneous spaces into mitochondrial matrix however the

membrane of mitochondria is impenetrable for protons

In mitochondria only АТP- synthetase (complex V) allows to carry out the re-

verse movement of protons from intermembranal spaces in mitochondrial matrix

and the same enzyme catalyses the formation of АТP ie synthesis АТP entails

the oxidation of substrate and then coferments and cofactors of respiratory cir-

cuit with participation of oxygen Therefore this process (oxidations and phos-

phorylation of АDP with formation of АТP) has received the name of oxidative

phosphorylation

АТP- synthetase consists of two parts the proton channel (13 subunits of pro-

tein) built in the internal membrane of mitochondria and catalyzed structure

acting in mitochondrial matrix (3 α - and 3 szlig-subunits)

Cycle of formation of АТP is divided into 3 phases

Linkage with the enzyme of АDP and Р

Formation of phosphoanhydrate bond between АDP and Р with the

formation of АТP

Releasing of end-products of the reaction (АТP and waters)

Calculation of the energy educed during the transport of electrons along

the respiratory circuit

Change of free energy (G) during the transport of electrons depends only on a

difference of oxidation-reduction potentials of the donor and the acceptor of

electrons in the respiratory circuit

The general value of the energy released at transport of 2е along the respiratory

circuit can be calculated

G0 = - n F E where

118

G0 - change of free standard energy

n- the number of transferred electrons (for example we shall take 2 of them)

F ndash Faraday number = 23062 cal

mole

E ndash Difference of standard potentials of components of the respiratory cir-

cuit giving (-032 volts) and accepting (+ 082 volts) electrons

Transfer of 2 electrons is accompanied with educing

G0 = - 2 23062 [082 ndash (- 032)] = - 526

kcalmole or (237

кjulemole)

- If protons enter the intermembraneous space through complexes I III

and IV 3 molecules АТP and coefficient of phosphorylation (rela-

tion PO)= 3 are formed if protons enter only through complexes II III

and IV 2 molecules АТP and coefficient of phosphorylation (PO)

= 2 are formed where Р ndash is the quantity of the inorganic phosphate in-

cluded in 2 or 3 АТP O- atom of oxygen on which 2 e- are transferred

- The reasons of conjugation oxidation and phosphorylation (oxidative

phosphorylation) are only on 3 or 2 parts of the respiratory circuit

- On other parts the potential difference of the connected redox-systems

(energy) is insufficient for the formation of АТP in these parts energy is

releasing as heat

- Uncouples of oxidative phosphorylation promote an expenditure of

proton potential without АТP-synthetase dissociation of phosphoryla-

tion and respiration is present

- Breath increases

- Phosphorylation is suppressed

- Heat production increases

- Uncouples of respiration and phosphorylations

- thermogenins

- Free fatty acids RCOO-+ Н + (on the external part of the membrane)

RCOOH reg RCOO-+ Н + (on the internal part of the membrane)

- 24-dinitrophenol salicylates (anti-inflammatory remedies)

- Peculiarities of the formation of heat in newborns and animals born

bald and also running into hibernation (brown fat and peculiarities of

their respiratory circuit organization)

- Brown fat in newborns

- They contain more mitochondria

- They have 10 times more enzymes of respiration than phosphorylation

- Presence of thermogenins in the membrane provides dissociation of res-

piration and phosphorylation that leads to formation of a plenty of heat

warming flowing blood

Regulation of energy exchange

For a day the requirement of an organism in energy (АТP) varies

The rate of the АТP formation depends on a energy status of cells iе correla-

tion

[ATP]

[ADP] [P]

119

At rest the energy charge of a cell changes is about 09 and comes nearer to 1

unit

[АТP] + frac12 [АDP]

[АTP] [АDP] + [АMP

At use of energy (АТP) by the organism a part of АТP is hydrolized up to АDP

and Р the enrgy charge of a cell is reduced

Increase of АDP concentration automatically will increase the rate of oxidizing

phosphorylation and the formations АТP ie the respiration of mitochondria is

checked with the help of АDP This mechanism of regulation of energy ex-

change of a cell has got the name ldquothe respiratory controlrdquo - there is no res-

piration if there is no ADP in the cell

Oxidizing mode of substrate oxidation

It is catalysed with mono-and dioxygenase

monoxygenases ndashis including of 1 atom of oxygen into the oxidized

substrate and the other one into the molecule of water according to the

scheme

R RO + H2O

dioxygenases - enzymes which catalyzed the reaction - including of both atoms

of oxygen in to the oxidizing substance

R +О2 RО2

microsomal oxidation is a version of the microsomal mode (enzymes of

oxidation - cytochromes Р450 are in microsomes)

- Bile acids

- - Steroid hormones

- - Heterologous substances (drugs toxins etc)

They are oxidazed according to oxygenase mode without educing energy

H

+ O2

H

RndashН + О2 RndashОН + Н2О

2еoline

NADPН2

FAD

Fe-protein

Р450

2Н+

120

Lipid Peroxidation (LP)

Active oxygen species (НО2- peroxide radical middotО2oline - superoxide radical middotОН-

hydroxyl radical) are capable to take hydrogen away from (-СН2-) the groups of

fatty acids transforming them into (-middotСН-) groups

Such radicals easily join molecules of oxygen and become a peroxyl radical of

fatty acids

ndashmiddotСНndash + О2 ndashСНndashОndashО

middot

The radical chain reaction begins when the peroxyl radical takes a hydrogen at-

om from the other fatty acid molecule thus stimulates free radical chain re-

actions

ndashСНndashОndashОmiddot + (ndashСН2ndash) ndashСНndashОndashОН + (ndash

middotСНndash)

Nonsaturated fatty acids which turn into peroxids and hydroperoxids of li-

pids are most sensitive to Lipid Peroxidation

Products of the LP - hydroperoxids of lipids spirits aldehydes malonic alde-

hyde ketons etc

Biological significance of Lipid Peroxidation

Regulation of renovating and permeability of lipid biological mem-

branes

In phagocytic cells for destruction of the absorbed bacteria and infec-

tious material Н2О2 and a superoxide radical which initiate the LP are

used and bacteria perish

Free radical processes can completely destroy nonsaturated lipids of

biomembranes of host cells causing inevitable destruction of cells

In the membranes of cells free radical processes are limited as there are various systems of protection against active forms of oxygen (antioxidant systems) in

cells

PERIOXIDIZATION MODE

R∙H2 + O2 rarr R + H2O2

Localization in peroxysomas (about 80 of H2O2 are formed) enzymes- ox-

ydase of amino acids amines etc

Biological significance

Amino acids biogenic amines and other organic molecules are oxidized

in such a way

Thus toxic for cells of an organism hydrogen peroxide H2O2 is formed

In leukocytes H2O2 is used for neutralization of pathogenic bacteria

In cells H2O2 is neutralized with the help of enzymes (catalase [E1] peroxydase

[E2])according to the scheme

2Н2О2 2Н2О + О2

Н2О2 + R Н2О + RO

121

Protection of membranes against LP

1 Inactivization of oxygen radicals under the action of superoxide

dismutase and catalase

2 Fermentative mechanism of membrane protection against LP un-

der the action of glutathione peroxidase

3 Chemical protection of membranes against LP with the help of anti-

oxidizers (the most powerful antioxidizer is Vitamin E)

110

HC - COOH

||

HC - COOH

fumarate

H2C - COOH

|

HO - C - COOH

|

H 2C - COOH

citrate

O

H3C - C

S - KoA

HS CoA

O = C - COOH

|

H2C - COOH

oxaloacetate

Н2О

H2C - COOH

|

C - COOH

||

HC - COOH

Cis-aconitate

СО2 NADН2 H2C - COOH

|

HC - COO H

|

HO - C - COOH

|

H

isocitrate

H2C - COOH

|

H2C- C - COO H

||

O

-ketoglutarate

NADН2

H2C - COOH

|

H2C - C ~ S KoA

||

O

succinyl CоА

GTP (АТP)

H2C - COOH

|

H2C - COOH

succinate

FADН2

ОН Н

HO - CH - COOH

|

H2C - COOH

malate

(малат)

NADН2

Н2О

Н S-CоА

СО2

Н2О

S CoA

proteins

lipids

carbohydrates

111

Biological role of the tricarbonoic acids cycle

integrative (amphibolic) ndash unites the catabolic and anabolic pathways of

carbohydrates lipids and proteins

catabolic and energetic ndash disintegration of Acetyl - CоА

- substrate phosphorylation in the tricarbonoic acids cycle (1

GTP = 1 АТP at the expense of the macroergs of succinyl-CоА)

- oxidative phosphorylation (3 NADН2-9 АТP

FADН2-2АТP only 11 АТP

- Total = 12 АТP

anabolic ndash substrats of the citric acid cycle are used for syn-

thesis of other substances

- oxaloacetate - aspartate glucose

ketoglutarate - glutamate

- succinyl-CоА - heme

Stages of proteins fats and carbohydrates anabolism

polysaccharides

proteins lipids

aminoacids monosaccharides

(glucose) fatty acids

ketoacids

pyruvate acetyle CoA

oxaloacetate

α-ketogluterate

succinate

Similarities and differences of processes of catabolism and anabolism (the place

of action enzymes coferments bio-energetics)

BIO-ENERGETICS of the CELL MECHANISMS of BIOLOGICAL OXIDATION

mdash The basic energy source for all organisms on the Earth is the sun radiation (as

a result of reactions of nuclear synthesis on the Sun)

III

II

I

g l y c e

r i n

112

mdash Photosynthesizing cells of plants catch the solar energy and use it on transfor-

mations of inorganic substances - СО2 Н2О and salts - in various rich energy

organic compounds (proteins lipids carbohydrates) Under the action of the

solar energy electrons of Н2О in the cells of plants are stimulated i е they

transfer (in the structure of proteins lipids carbohydrates) into higher energet-

ic level

mdash During disintegration of proteins fats and carbohydrates in an organism of an-

imals the return transition of electrons into lower power orbit with the for-

mation of Н2О take place which is accompanied by releasing the same quantity

of energy Hence the basic carrier of energy -electron and its source - the Sun

Laws of thermodynamics

Forms of energy (thermal chemical electric etc) and the communications exist-

ing between various forms of energy (opportunities of transformation) which

are formulated in the laws of thermodynamics

The first law of thermodynamics

sect Energy neither disappear nor arise it is only transforms from one form

into another

The second law of thermodynamics (entropy)

sect All spontaneous processes in the systems proceed only in one direction -

reduction of free energy that is not seldom accompanied by increase the

systems disorder (entropy)

The conditions necessary for preservation of homeostage of alive organisms

(constancy of the internal medium) ndash entering energy in it since processes of

disintegration are constantly present

Mathematical calculation of change of free energy

G = H ndash Т S where

G - a part of energy of the system which is spent for fulfillment of work

(kjulemole substances)

H -Change in heat contents of the system (enthalpy)

Т - absolute temperature

S - entropy change disorder of the systems

The energy enters animals organism in the form of proteins carbohydrates and

lipids catabolism of which conducts to becoming this energy free and its trans-

formation into

Energy of macroergs (АТP etc)

Electric energy

Thermal energy

Mechanical one

Energy of chemical bonds etc

113

High-energy (macroergs) and low-energy compounds of animals tissue АТP - universal macroergs in plants and animals world

macroergic compounds are called the substances having macroergic bond

macroergic bond is marked by ldquo~rdquo Energy is used for satisfaction of

energy needs of a cell

compound product of reaction -G kjulemole

phosphoenolpyruvate pyruvate + Н3РО4 619

13-bisphosphoglycerate 3-phosphoglycerate+Н3РО4 545

carbamoylphosphate carbamate + Н3РО4 515

creatinephosphate creatine + Н3РО4 431

pyrophosphate Н4Р2О7 2 Н3РО4 334

Acetyle-CoA acetate +HS-CоА 350

Succinyle-CoA succinate + HS-CoA 435

АТP (GTPUTP etc) ADP + Н3РО4 345 (~73 kcalmole)

ADP АМP + Н3РО4 363

АМP adenosine + Н3РО4 96

glycerophosphate glycerine + Н3РО4 92

glucose-6-phosphate glucose + Н3РО4 138

- Universal macroerg is ATP Its molecule serves as a part connecting among them-

selves various kinds of transformation of energy chemical mechanical electric

osmotic and other processes going with release and consumption of energy

- The reasons of release of energy at hydrolysis of macroergic bond (phospho-

anhydtate) of АТP and АDP

Redistribution of electrons on orbits

pH medium (neutral)

Significance of dissociation (АТP-4 АDP-3 АМP-2)

- Daily requirement of the adult for energy (АТP) and real presence АТP in an or-

ganism (˜65kg available 3-4g)

- Reactions n of АDP rephosphorylatio and subsequent use of АТP as an energy

source (dephosphorylation) form the cycle which repeats 25-3 thousand times per day

The diagram of the formation and use of АТP in an organism

Solar energy

plants cells (carbohy-

drates lipids proteins)

feeding of animals

Energy of

Carbohydrates lipids pro-

teins

АТP

АDP + Н3РО4

biosynthesis

Muscular reduction

Active transport of ions

through membranes (po-

tential of rest and potential

of action)

Other volatile processes

energydependent

(body temperature)

re

ph

osp

ho

ryla

tio

n

Dep

ho

sph

ory

latio

n

114

2 modes of ADP rephosphorylation

Oxidative phosphorylation

Substrate phosphorylation

The main substrates for rephosphorylation of АDP oxidation of proteins fats

and carbohydrates in tissues during their oxidation

Variants of oxidation of organic substances in animal tissues

oxidase type (dehydration and transport of electrons and protons on oxy-

gen with the formation of energy Н2О СО2) oxigenase (oxidations of a substrate by oxygen)

mechanisms of peroxide oxidation of lipids

peroxidase type (oxidation of a substrate with the formation of hydrogen

peroxide and use of the latter for oxidation of other substrates)

Oxidase type of oxidations of proteins lipids carbohydrates (cell respiration of

tissues) is the basic mode of oxidation in tissues of animals and at the same time it manu-

factures energy (АТP and heat)

Oxidase type of oxidation of substrates is provided with enzymes and coferments of

the respiratory circuit

Chemical compound of components of a respiratory circuit and their

redox-potential

Components of a respiratory circuit are collected from the set of enzymes and

polypeptides which contain a number of various oxidizing and restored

coferments and cofactors (iron copper) as a prostetic group

Е0В ndash042 ndash 032 + 004 + 007 + 023 + 025 + 029 + 055 + 082

Н NAD (FMN) Ко Q b Fe3+

c1 Fe3+

c Fe3+

a Fe3+

a3 (Cu2+

Fe3+

) 12O2

R

Н NADН2 Ко Q Н2 b Fe2+

c1 Fe2+

c Fe2+

a Fe2+

a3 (Cu+Fe

2+) Н2О

And also Fes protein ATP ATP ATP

cytochromes dehydrogenase

ndash 005

FAD

FADН2

(2)

(1)

115

The redox-potential is characterized by the energy which is released at transporting electrons from the given substance on a hydrogen electrode and is ex-

pressed in electron-volts

o The redox-potential and the function of components of the respiratory circuit depend on a chemical nature and correlation of the oxidized and

restored molecules included in their structure

o Members of oxidation-reduction lines settle down in ascending order of potentials [-032В - (+082В)]

o Components of the respiratory circuit in mitochondria are organized in complexes (the circuit is on page 15)

The respiratory circuit includes four albuminous complexes (I III IV V) built - in the internal mitochondrial membrane and two mobile systems mole-

cules - carriers - ubiquinone (КоQ) and cytochromes C Succinate dehydrogenase from cycle TCA is also considered as well as the complex of II respiratory

circuit

complex I ( NADН-dehydrogenase + FMN +FeS-proteins)

complex II ( succinate dehydrogenase + FAD +FeS-proteins)

complex III (cytochromendashC- reductase contents cytochromes b c1 и FeS-proteins)

complex IV (cytochrome-C- oxidase contents cytochromes а and а3 Сu)

complex V ( АТP-synthase)

electrons and protons enter the respiratory circuit in two ways

in the oxidation of NADН2 complex 1 transfers electrons and protons through FMN and FeS-protein on ubiquinone

in oxidation succinate electrons and protons are transferred on ubiquinone by complex II containing FADН2-dehydrogenase and FeS-protein

As a result in both cases the oxidized form of ubiquinone (КоQ) is restored up to ubihydrochinone (КоQН2)

Then the electrons from КоQН2 are transferred along the circuit by complex III on cytochrome C

cytochrome C transfers electrons to complex IV in which cytochrome а3 has unique properties - ability to transfer electrons on 12О2 with the for-

mation of О-2

ion which joins the protons removed from oxidized substrates through dehydrogenase and KoQ Endogenic water is formed

In the human organism as a result of cell respiration (tissue) 300 - 400 ml of water is formed for a day endogenic or metabolic water (camels in a de-

sert bears - hibernation in a den)

Complete restoration of О2 up to Н2О requires joining 4 е-

In an organism restoration of oxygen occurs stage by stage transferring 1еndash at each stage

Joining the first еndash forms superoxide anion О2

ndash

Joining two еndash forms peroxide anion О2

2ndashН2О2

Peroxide of hydrogen and superoxide radical are very toxic They are destroyed in a cell the first ndash by catalase the second ndash by superoxiddismutase

116

The organization of complexes I-V from the components of the respiratory circuit in mitochondria (scheme)

3 ADP + 3 Pi

Pro

tein

sli

pid

samp c

arb

o-

hydra

tes

of

food

АТP- synthetase

complex V complex I

NADН-dehydrogenase

FMN + FeS - protein

complex III

cytochrome c - reductase (cytochrome bc1)

and FeS - proteins

complex IV

Cytochrome C oxidase

cytochrome аа3 Cu)

КоQ

2е-+2Н

+ e-rarr

e-rarr

cytochrome

С rarre

-rarr

rarre-rarr

Ex

tern

al m

em-

bra

ne

of

mit

o-

cho

ndri

a

Inte

rnal

mem

-b

ran

e of

mit

o-

cho

ndri

a

Intercellular space

4Н2Оharr4 Н++ 4ОН

-

com

ple

x I

I

Su

ccin

ate

deh

yd

rog

enes

is

T C A

Acetyle-CoA

pyru

vat

e

acey

l-C

oA

2Н

++

2е- 4Н2Оharr4 Н

++ 4ОН

-

2Н+

4Н+

2Н

++

2е-

2Н2Оharr2 Н++ 2ОН

-

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

+ + + + + 4Н+ + + + + + + + 2Н

+ +

ОН- ОН

- ОН

-

2Н+

+12О2

12О2

2е-

Н2О

Matrix of

mitochondria

10Н+

10ОН-

10Н2О

3 А

ТP

+

hea

t NADН2

FA

DH

2

Endogenic water

(300-400 ml per day)

О2 + e- О2ˉ (superoxide anion)

О2ˉ+ e- О2

2ˉ (peroxide anion)

О2ˉ +e-+ 2H

+ H2О2 (peroxide of hydrogen)

H2О2+ О2ˉ OHˉ + OH + O2 (hydroxyle

anion and hydroxyle radical)

117

Together with electrons complexes I III and IV due to the energy of electrons

transferring of protons from mitochondrial matrix (Н + are formed at dissocia-

tion of waters) is vectorially made into intermembraneous space where the con-

centration of ions Н+ increases and on a membrane the proton potential Н +

is formed

Biological sense of electrons transport along the respira-tory circuit and transfer of protons into the intermembra-

neous space (chemiosmatic hypothesis of Mitchel -Sculachev)

Transfer of electrons along the respiratory circuit is accompanied with the

gradual releasing energy the part of which (~ 40 ) is used for the formation

of АТP and other energy dissipates as heat (heatproduction)

Energy of electrons is used for the formation of a proton gradient on the inter-

nal mitochondrial membrane The proton potential appears (an electrochemical

gradient of ions Н + Н +)

Formation of АТP (oxidative phosphorylation) entails the reverse stream of

protons from intermembraneous spaces into mitochondrial matrix however the

membrane of mitochondria is impenetrable for protons

In mitochondria only АТP- synthetase (complex V) allows to carry out the re-

verse movement of protons from intermembranal spaces in mitochondrial matrix

and the same enzyme catalyses the formation of АТP ie synthesis АТP entails

the oxidation of substrate and then coferments and cofactors of respiratory cir-

cuit with participation of oxygen Therefore this process (oxidations and phos-

phorylation of АDP with formation of АТP) has received the name of oxidative

phosphorylation

АТP- synthetase consists of two parts the proton channel (13 subunits of pro-

tein) built in the internal membrane of mitochondria and catalyzed structure

acting in mitochondrial matrix (3 α - and 3 szlig-subunits)

Cycle of formation of АТP is divided into 3 phases

Linkage with the enzyme of АDP and Р

Formation of phosphoanhydrate bond between АDP and Р with the

formation of АТP

Releasing of end-products of the reaction (АТP and waters)

Calculation of the energy educed during the transport of electrons along

the respiratory circuit

Change of free energy (G) during the transport of electrons depends only on a

difference of oxidation-reduction potentials of the donor and the acceptor of

electrons in the respiratory circuit

The general value of the energy released at transport of 2е along the respiratory

circuit can be calculated

G0 = - n F E where

118

G0 - change of free standard energy

n- the number of transferred electrons (for example we shall take 2 of them)

F ndash Faraday number = 23062 cal

mole

E ndash Difference of standard potentials of components of the respiratory cir-

cuit giving (-032 volts) and accepting (+ 082 volts) electrons

Transfer of 2 electrons is accompanied with educing

G0 = - 2 23062 [082 ndash (- 032)] = - 526

kcalmole or (237

кjulemole)

- If protons enter the intermembraneous space through complexes I III

and IV 3 molecules АТP and coefficient of phosphorylation (rela-

tion PO)= 3 are formed if protons enter only through complexes II III

and IV 2 molecules АТP and coefficient of phosphorylation (PO)

= 2 are formed where Р ndash is the quantity of the inorganic phosphate in-

cluded in 2 or 3 АТP O- atom of oxygen on which 2 e- are transferred

- The reasons of conjugation oxidation and phosphorylation (oxidative

phosphorylation) are only on 3 or 2 parts of the respiratory circuit

- On other parts the potential difference of the connected redox-systems

(energy) is insufficient for the formation of АТP in these parts energy is

releasing as heat

- Uncouples of oxidative phosphorylation promote an expenditure of

proton potential without АТP-synthetase dissociation of phosphoryla-

tion and respiration is present

- Breath increases

- Phosphorylation is suppressed

- Heat production increases

- Uncouples of respiration and phosphorylations

- thermogenins

- Free fatty acids RCOO-+ Н + (on the external part of the membrane)

RCOOH reg RCOO-+ Н + (on the internal part of the membrane)

- 24-dinitrophenol salicylates (anti-inflammatory remedies)

- Peculiarities of the formation of heat in newborns and animals born

bald and also running into hibernation (brown fat and peculiarities of

their respiratory circuit organization)

- Brown fat in newborns

- They contain more mitochondria

- They have 10 times more enzymes of respiration than phosphorylation

- Presence of thermogenins in the membrane provides dissociation of res-

piration and phosphorylation that leads to formation of a plenty of heat

warming flowing blood

Regulation of energy exchange

For a day the requirement of an organism in energy (АТP) varies

The rate of the АТP formation depends on a energy status of cells iе correla-

tion

[ATP]

[ADP] [P]

119

At rest the energy charge of a cell changes is about 09 and comes nearer to 1

unit

[АТP] + frac12 [АDP]

[АTP] [АDP] + [АMP

At use of energy (АТP) by the organism a part of АТP is hydrolized up to АDP

and Р the enrgy charge of a cell is reduced

Increase of АDP concentration automatically will increase the rate of oxidizing

phosphorylation and the formations АТP ie the respiration of mitochondria is

checked with the help of АDP This mechanism of regulation of energy ex-

change of a cell has got the name ldquothe respiratory controlrdquo - there is no res-

piration if there is no ADP in the cell

Oxidizing mode of substrate oxidation

It is catalysed with mono-and dioxygenase

monoxygenases ndashis including of 1 atom of oxygen into the oxidized

substrate and the other one into the molecule of water according to the

scheme

R RO + H2O

dioxygenases - enzymes which catalyzed the reaction - including of both atoms

of oxygen in to the oxidizing substance

R +О2 RО2

microsomal oxidation is a version of the microsomal mode (enzymes of

oxidation - cytochromes Р450 are in microsomes)

- Bile acids

- - Steroid hormones

- - Heterologous substances (drugs toxins etc)

They are oxidazed according to oxygenase mode without educing energy

H

+ O2

H

RndashН + О2 RndashОН + Н2О

2еoline

NADPН2

FAD

Fe-protein

Р450

2Н+

120

Lipid Peroxidation (LP)

Active oxygen species (НО2- peroxide radical middotО2oline - superoxide radical middotОН-

hydroxyl radical) are capable to take hydrogen away from (-СН2-) the groups of

fatty acids transforming them into (-middotСН-) groups

Such radicals easily join molecules of oxygen and become a peroxyl radical of

fatty acids

ndashmiddotСНndash + О2 ndashСНndashОndashО

middot

The radical chain reaction begins when the peroxyl radical takes a hydrogen at-

om from the other fatty acid molecule thus stimulates free radical chain re-

actions

ndashСНndashОndashОmiddot + (ndashСН2ndash) ndashСНndashОndashОН + (ndash

middotСНndash)

Nonsaturated fatty acids which turn into peroxids and hydroperoxids of li-

pids are most sensitive to Lipid Peroxidation

Products of the LP - hydroperoxids of lipids spirits aldehydes malonic alde-

hyde ketons etc

Biological significance of Lipid Peroxidation

Regulation of renovating and permeability of lipid biological mem-

branes

In phagocytic cells for destruction of the absorbed bacteria and infec-

tious material Н2О2 and a superoxide radical which initiate the LP are

used and bacteria perish

Free radical processes can completely destroy nonsaturated lipids of

biomembranes of host cells causing inevitable destruction of cells

In the membranes of cells free radical processes are limited as there are various systems of protection against active forms of oxygen (antioxidant systems) in

cells

PERIOXIDIZATION MODE

R∙H2 + O2 rarr R + H2O2

Localization in peroxysomas (about 80 of H2O2 are formed) enzymes- ox-

ydase of amino acids amines etc

Biological significance

Amino acids biogenic amines and other organic molecules are oxidized

in such a way

Thus toxic for cells of an organism hydrogen peroxide H2O2 is formed

In leukocytes H2O2 is used for neutralization of pathogenic bacteria

In cells H2O2 is neutralized with the help of enzymes (catalase [E1] peroxydase

[E2])according to the scheme

2Н2О2 2Н2О + О2

Н2О2 + R Н2О + RO

121

Protection of membranes against LP

1 Inactivization of oxygen radicals under the action of superoxide

dismutase and catalase

2 Fermentative mechanism of membrane protection against LP un-

der the action of glutathione peroxidase

3 Chemical protection of membranes against LP with the help of anti-

oxidizers (the most powerful antioxidizer is Vitamin E)

111

Biological role of the tricarbonoic acids cycle

integrative (amphibolic) ndash unites the catabolic and anabolic pathways of

carbohydrates lipids and proteins

catabolic and energetic ndash disintegration of Acetyl - CоА

- substrate phosphorylation in the tricarbonoic acids cycle (1

GTP = 1 АТP at the expense of the macroergs of succinyl-CоА)

- oxidative phosphorylation (3 NADН2-9 АТP

FADН2-2АТP only 11 АТP

- Total = 12 АТP

anabolic ndash substrats of the citric acid cycle are used for syn-

thesis of other substances

- oxaloacetate - aspartate glucose

ketoglutarate - glutamate

- succinyl-CоА - heme

Stages of proteins fats and carbohydrates anabolism

polysaccharides

proteins lipids

aminoacids monosaccharides

(glucose) fatty acids

ketoacids

pyruvate acetyle CoA

oxaloacetate

α-ketogluterate

succinate

Similarities and differences of processes of catabolism and anabolism (the place

of action enzymes coferments bio-energetics)

BIO-ENERGETICS of the CELL MECHANISMS of BIOLOGICAL OXIDATION

mdash The basic energy source for all organisms on the Earth is the sun radiation (as

a result of reactions of nuclear synthesis on the Sun)

III

II

I

g l y c e

r i n

112

mdash Photosynthesizing cells of plants catch the solar energy and use it on transfor-

mations of inorganic substances - СО2 Н2О and salts - in various rich energy

organic compounds (proteins lipids carbohydrates) Under the action of the

solar energy electrons of Н2О in the cells of plants are stimulated i е they

transfer (in the structure of proteins lipids carbohydrates) into higher energet-

ic level

mdash During disintegration of proteins fats and carbohydrates in an organism of an-

imals the return transition of electrons into lower power orbit with the for-

mation of Н2О take place which is accompanied by releasing the same quantity

of energy Hence the basic carrier of energy -electron and its source - the Sun

Laws of thermodynamics

Forms of energy (thermal chemical electric etc) and the communications exist-

ing between various forms of energy (opportunities of transformation) which

are formulated in the laws of thermodynamics

The first law of thermodynamics

sect Energy neither disappear nor arise it is only transforms from one form

into another

The second law of thermodynamics (entropy)

sect All spontaneous processes in the systems proceed only in one direction -

reduction of free energy that is not seldom accompanied by increase the

systems disorder (entropy)

The conditions necessary for preservation of homeostage of alive organisms

(constancy of the internal medium) ndash entering energy in it since processes of

disintegration are constantly present

Mathematical calculation of change of free energy

G = H ndash Т S where

G - a part of energy of the system which is spent for fulfillment of work

(kjulemole substances)

H -Change in heat contents of the system (enthalpy)

Т - absolute temperature

S - entropy change disorder of the systems

The energy enters animals organism in the form of proteins carbohydrates and

lipids catabolism of which conducts to becoming this energy free and its trans-

formation into

Energy of macroergs (АТP etc)

Electric energy

Thermal energy

Mechanical one

Energy of chemical bonds etc

113

High-energy (macroergs) and low-energy compounds of animals tissue АТP - universal macroergs in plants and animals world

macroergic compounds are called the substances having macroergic bond

macroergic bond is marked by ldquo~rdquo Energy is used for satisfaction of

energy needs of a cell

compound product of reaction -G kjulemole

phosphoenolpyruvate pyruvate + Н3РО4 619

13-bisphosphoglycerate 3-phosphoglycerate+Н3РО4 545

carbamoylphosphate carbamate + Н3РО4 515

creatinephosphate creatine + Н3РО4 431

pyrophosphate Н4Р2О7 2 Н3РО4 334

Acetyle-CoA acetate +HS-CоА 350

Succinyle-CoA succinate + HS-CoA 435

АТP (GTPUTP etc) ADP + Н3РО4 345 (~73 kcalmole)

ADP АМP + Н3РО4 363

АМP adenosine + Н3РО4 96

glycerophosphate glycerine + Н3РО4 92

glucose-6-phosphate glucose + Н3РО4 138

- Universal macroerg is ATP Its molecule serves as a part connecting among them-

selves various kinds of transformation of energy chemical mechanical electric

osmotic and other processes going with release and consumption of energy

- The reasons of release of energy at hydrolysis of macroergic bond (phospho-

anhydtate) of АТP and АDP

Redistribution of electrons on orbits

pH medium (neutral)

Significance of dissociation (АТP-4 АDP-3 АМP-2)

- Daily requirement of the adult for energy (АТP) and real presence АТP in an or-

ganism (˜65kg available 3-4g)

- Reactions n of АDP rephosphorylatio and subsequent use of АТP as an energy

source (dephosphorylation) form the cycle which repeats 25-3 thousand times per day

The diagram of the formation and use of АТP in an organism

Solar energy

plants cells (carbohy-

drates lipids proteins)

feeding of animals

Energy of

Carbohydrates lipids pro-

teins

АТP

АDP + Н3РО4

biosynthesis

Muscular reduction

Active transport of ions

through membranes (po-

tential of rest and potential

of action)

Other volatile processes

energydependent

(body temperature)

re

ph

osp

ho

ryla

tio

n

Dep

ho

sph

ory

latio

n

114

2 modes of ADP rephosphorylation

Oxidative phosphorylation

Substrate phosphorylation

The main substrates for rephosphorylation of АDP oxidation of proteins fats

and carbohydrates in tissues during their oxidation

Variants of oxidation of organic substances in animal tissues

oxidase type (dehydration and transport of electrons and protons on oxy-

gen with the formation of energy Н2О СО2) oxigenase (oxidations of a substrate by oxygen)

mechanisms of peroxide oxidation of lipids

peroxidase type (oxidation of a substrate with the formation of hydrogen

peroxide and use of the latter for oxidation of other substrates)

Oxidase type of oxidations of proteins lipids carbohydrates (cell respiration of

tissues) is the basic mode of oxidation in tissues of animals and at the same time it manu-

factures energy (АТP and heat)

Oxidase type of oxidation of substrates is provided with enzymes and coferments of

the respiratory circuit

Chemical compound of components of a respiratory circuit and their

redox-potential

Components of a respiratory circuit are collected from the set of enzymes and

polypeptides which contain a number of various oxidizing and restored

coferments and cofactors (iron copper) as a prostetic group

Е0В ndash042 ndash 032 + 004 + 007 + 023 + 025 + 029 + 055 + 082

Н NAD (FMN) Ко Q b Fe3+

c1 Fe3+

c Fe3+

a Fe3+

a3 (Cu2+

Fe3+

) 12O2

R

Н NADН2 Ко Q Н2 b Fe2+

c1 Fe2+

c Fe2+

a Fe2+

a3 (Cu+Fe

2+) Н2О

And also Fes protein ATP ATP ATP

cytochromes dehydrogenase

ndash 005

FAD

FADН2

(2)

(1)

115

The redox-potential is characterized by the energy which is released at transporting electrons from the given substance on a hydrogen electrode and is ex-

pressed in electron-volts

o The redox-potential and the function of components of the respiratory circuit depend on a chemical nature and correlation of the oxidized and

restored molecules included in their structure

o Members of oxidation-reduction lines settle down in ascending order of potentials [-032В - (+082В)]

o Components of the respiratory circuit in mitochondria are organized in complexes (the circuit is on page 15)

The respiratory circuit includes four albuminous complexes (I III IV V) built - in the internal mitochondrial membrane and two mobile systems mole-

cules - carriers - ubiquinone (КоQ) and cytochromes C Succinate dehydrogenase from cycle TCA is also considered as well as the complex of II respiratory

circuit

complex I ( NADН-dehydrogenase + FMN +FeS-proteins)

complex II ( succinate dehydrogenase + FAD +FeS-proteins)

complex III (cytochromendashC- reductase contents cytochromes b c1 и FeS-proteins)

complex IV (cytochrome-C- oxidase contents cytochromes а and а3 Сu)

complex V ( АТP-synthase)

electrons and protons enter the respiratory circuit in two ways

in the oxidation of NADН2 complex 1 transfers electrons and protons through FMN and FeS-protein on ubiquinone

in oxidation succinate electrons and protons are transferred on ubiquinone by complex II containing FADН2-dehydrogenase and FeS-protein

As a result in both cases the oxidized form of ubiquinone (КоQ) is restored up to ubihydrochinone (КоQН2)

Then the electrons from КоQН2 are transferred along the circuit by complex III on cytochrome C

cytochrome C transfers electrons to complex IV in which cytochrome а3 has unique properties - ability to transfer electrons on 12О2 with the for-

mation of О-2

ion which joins the protons removed from oxidized substrates through dehydrogenase and KoQ Endogenic water is formed

In the human organism as a result of cell respiration (tissue) 300 - 400 ml of water is formed for a day endogenic or metabolic water (camels in a de-

sert bears - hibernation in a den)

Complete restoration of О2 up to Н2О requires joining 4 е-

In an organism restoration of oxygen occurs stage by stage transferring 1еndash at each stage

Joining the first еndash forms superoxide anion О2

ndash

Joining two еndash forms peroxide anion О2

2ndashН2О2

Peroxide of hydrogen and superoxide radical are very toxic They are destroyed in a cell the first ndash by catalase the second ndash by superoxiddismutase

116

The organization of complexes I-V from the components of the respiratory circuit in mitochondria (scheme)

3 ADP + 3 Pi

Pro

tein

sli

pid

samp c

arb

o-

hydra

tes

of

food

АТP- synthetase

complex V complex I

NADН-dehydrogenase

FMN + FeS - protein

complex III

cytochrome c - reductase (cytochrome bc1)

and FeS - proteins

complex IV

Cytochrome C oxidase

cytochrome аа3 Cu)

КоQ

2е-+2Н

+ e-rarr

e-rarr

cytochrome

С rarre

-rarr

rarre-rarr

Ex

tern

al m

em-

bra

ne

of

mit

o-

cho

ndri

a

Inte

rnal

mem

-b

ran

e of

mit

o-

cho

ndri

a

Intercellular space

4Н2Оharr4 Н++ 4ОН

-

com

ple

x I

I

Su

ccin

ate

deh

yd

rog

enes

is

T C A

Acetyle-CoA

pyru

vat

e

acey

l-C

oA

2Н

++

2е- 4Н2Оharr4 Н

++ 4ОН

-

2Н+

4Н+

2Н

++

2е-

2Н2Оharr2 Н++ 2ОН

-

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

+ + + + + 4Н+ + + + + + + + 2Н

+ +

ОН- ОН

- ОН

-

2Н+

+12О2

12О2

2е-

Н2О

Matrix of

mitochondria

10Н+

10ОН-

10Н2О

3 А

ТP

+

hea

t NADН2

FA

DH

2

Endogenic water

(300-400 ml per day)

О2 + e- О2ˉ (superoxide anion)

О2ˉ+ e- О2

2ˉ (peroxide anion)

О2ˉ +e-+ 2H

+ H2О2 (peroxide of hydrogen)

H2О2+ О2ˉ OHˉ + OH + O2 (hydroxyle

anion and hydroxyle radical)

117

Together with electrons complexes I III and IV due to the energy of electrons

transferring of protons from mitochondrial matrix (Н + are formed at dissocia-

tion of waters) is vectorially made into intermembraneous space where the con-

centration of ions Н+ increases and on a membrane the proton potential Н +

is formed

Biological sense of electrons transport along the respira-tory circuit and transfer of protons into the intermembra-

neous space (chemiosmatic hypothesis of Mitchel -Sculachev)

Transfer of electrons along the respiratory circuit is accompanied with the

gradual releasing energy the part of which (~ 40 ) is used for the formation

of АТP and other energy dissipates as heat (heatproduction)

Energy of electrons is used for the formation of a proton gradient on the inter-

nal mitochondrial membrane The proton potential appears (an electrochemical

gradient of ions Н + Н +)

Formation of АТP (oxidative phosphorylation) entails the reverse stream of

protons from intermembraneous spaces into mitochondrial matrix however the

membrane of mitochondria is impenetrable for protons

In mitochondria only АТP- synthetase (complex V) allows to carry out the re-

verse movement of protons from intermembranal spaces in mitochondrial matrix

and the same enzyme catalyses the formation of АТP ie synthesis АТP entails

the oxidation of substrate and then coferments and cofactors of respiratory cir-

cuit with participation of oxygen Therefore this process (oxidations and phos-

phorylation of АDP with formation of АТP) has received the name of oxidative

phosphorylation

АТP- synthetase consists of two parts the proton channel (13 subunits of pro-

tein) built in the internal membrane of mitochondria and catalyzed structure

acting in mitochondrial matrix (3 α - and 3 szlig-subunits)

Cycle of formation of АТP is divided into 3 phases

Linkage with the enzyme of АDP and Р

Formation of phosphoanhydrate bond between АDP and Р with the

formation of АТP

Releasing of end-products of the reaction (АТP and waters)

Calculation of the energy educed during the transport of electrons along

the respiratory circuit

Change of free energy (G) during the transport of electrons depends only on a

difference of oxidation-reduction potentials of the donor and the acceptor of

electrons in the respiratory circuit

The general value of the energy released at transport of 2е along the respiratory

circuit can be calculated

G0 = - n F E where

118

G0 - change of free standard energy

n- the number of transferred electrons (for example we shall take 2 of them)

F ndash Faraday number = 23062 cal

mole

E ndash Difference of standard potentials of components of the respiratory cir-

cuit giving (-032 volts) and accepting (+ 082 volts) electrons

Transfer of 2 electrons is accompanied with educing

G0 = - 2 23062 [082 ndash (- 032)] = - 526

kcalmole or (237

кjulemole)

- If protons enter the intermembraneous space through complexes I III

and IV 3 molecules АТP and coefficient of phosphorylation (rela-

tion PO)= 3 are formed if protons enter only through complexes II III

and IV 2 molecules АТP and coefficient of phosphorylation (PO)

= 2 are formed where Р ndash is the quantity of the inorganic phosphate in-

cluded in 2 or 3 АТP O- atom of oxygen on which 2 e- are transferred

- The reasons of conjugation oxidation and phosphorylation (oxidative

phosphorylation) are only on 3 or 2 parts of the respiratory circuit

- On other parts the potential difference of the connected redox-systems

(energy) is insufficient for the formation of АТP in these parts energy is

releasing as heat

- Uncouples of oxidative phosphorylation promote an expenditure of

proton potential without АТP-synthetase dissociation of phosphoryla-

tion and respiration is present

- Breath increases

- Phosphorylation is suppressed

- Heat production increases

- Uncouples of respiration and phosphorylations

- thermogenins

- Free fatty acids RCOO-+ Н + (on the external part of the membrane)

RCOOH reg RCOO-+ Н + (on the internal part of the membrane)

- 24-dinitrophenol salicylates (anti-inflammatory remedies)

- Peculiarities of the formation of heat in newborns and animals born

bald and also running into hibernation (brown fat and peculiarities of

their respiratory circuit organization)

- Brown fat in newborns

- They contain more mitochondria

- They have 10 times more enzymes of respiration than phosphorylation

- Presence of thermogenins in the membrane provides dissociation of res-

piration and phosphorylation that leads to formation of a plenty of heat

warming flowing blood

Regulation of energy exchange

For a day the requirement of an organism in energy (АТP) varies

The rate of the АТP formation depends on a energy status of cells iе correla-

tion

[ATP]

[ADP] [P]

119

At rest the energy charge of a cell changes is about 09 and comes nearer to 1

unit

[АТP] + frac12 [АDP]

[АTP] [АDP] + [АMP

At use of energy (АТP) by the organism a part of АТP is hydrolized up to АDP

and Р the enrgy charge of a cell is reduced

Increase of АDP concentration automatically will increase the rate of oxidizing

phosphorylation and the formations АТP ie the respiration of mitochondria is

checked with the help of АDP This mechanism of regulation of energy ex-

change of a cell has got the name ldquothe respiratory controlrdquo - there is no res-

piration if there is no ADP in the cell

Oxidizing mode of substrate oxidation

It is catalysed with mono-and dioxygenase

monoxygenases ndashis including of 1 atom of oxygen into the oxidized

substrate and the other one into the molecule of water according to the

scheme

R RO + H2O

dioxygenases - enzymes which catalyzed the reaction - including of both atoms

of oxygen in to the oxidizing substance

R +О2 RО2

microsomal oxidation is a version of the microsomal mode (enzymes of

oxidation - cytochromes Р450 are in microsomes)

- Bile acids

- - Steroid hormones

- - Heterologous substances (drugs toxins etc)

They are oxidazed according to oxygenase mode without educing energy

H

+ O2

H

RndashН + О2 RndashОН + Н2О

2еoline

NADPН2

FAD

Fe-protein

Р450

2Н+

120

Lipid Peroxidation (LP)

Active oxygen species (НО2- peroxide radical middotО2oline - superoxide radical middotОН-

hydroxyl radical) are capable to take hydrogen away from (-СН2-) the groups of

fatty acids transforming them into (-middotСН-) groups

Such radicals easily join molecules of oxygen and become a peroxyl radical of

fatty acids

ndashmiddotСНndash + О2 ndashСНndashОndashО

middot

The radical chain reaction begins when the peroxyl radical takes a hydrogen at-

om from the other fatty acid molecule thus stimulates free radical chain re-

actions

ndashСНndashОndashОmiddot + (ndashСН2ndash) ndashСНndashОndashОН + (ndash

middotСНndash)

Nonsaturated fatty acids which turn into peroxids and hydroperoxids of li-

pids are most sensitive to Lipid Peroxidation

Products of the LP - hydroperoxids of lipids spirits aldehydes malonic alde-

hyde ketons etc

Biological significance of Lipid Peroxidation

Regulation of renovating and permeability of lipid biological mem-

branes

In phagocytic cells for destruction of the absorbed bacteria and infec-

tious material Н2О2 and a superoxide radical which initiate the LP are

used and bacteria perish

Free radical processes can completely destroy nonsaturated lipids of

biomembranes of host cells causing inevitable destruction of cells

In the membranes of cells free radical processes are limited as there are various systems of protection against active forms of oxygen (antioxidant systems) in

cells

PERIOXIDIZATION MODE

R∙H2 + O2 rarr R + H2O2

Localization in peroxysomas (about 80 of H2O2 are formed) enzymes- ox-

ydase of amino acids amines etc

Biological significance

Amino acids biogenic amines and other organic molecules are oxidized

in such a way

Thus toxic for cells of an organism hydrogen peroxide H2O2 is formed

In leukocytes H2O2 is used for neutralization of pathogenic bacteria

In cells H2O2 is neutralized with the help of enzymes (catalase [E1] peroxydase

[E2])according to the scheme

2Н2О2 2Н2О + О2

Н2О2 + R Н2О + RO

121

Protection of membranes against LP

1 Inactivization of oxygen radicals under the action of superoxide

dismutase and catalase

2 Fermentative mechanism of membrane protection against LP un-

der the action of glutathione peroxidase

3 Chemical protection of membranes against LP with the help of anti-

oxidizers (the most powerful antioxidizer is Vitamin E)

112

mdash Photosynthesizing cells of plants catch the solar energy and use it on transfor-

mations of inorganic substances - СО2 Н2О and salts - in various rich energy

organic compounds (proteins lipids carbohydrates) Under the action of the

solar energy electrons of Н2О in the cells of plants are stimulated i е they

transfer (in the structure of proteins lipids carbohydrates) into higher energet-

ic level

mdash During disintegration of proteins fats and carbohydrates in an organism of an-

imals the return transition of electrons into lower power orbit with the for-

mation of Н2О take place which is accompanied by releasing the same quantity

of energy Hence the basic carrier of energy -electron and its source - the Sun

Laws of thermodynamics

Forms of energy (thermal chemical electric etc) and the communications exist-

ing between various forms of energy (opportunities of transformation) which

are formulated in the laws of thermodynamics

The first law of thermodynamics

sect Energy neither disappear nor arise it is only transforms from one form

into another

The second law of thermodynamics (entropy)

sect All spontaneous processes in the systems proceed only in one direction -

reduction of free energy that is not seldom accompanied by increase the

systems disorder (entropy)

The conditions necessary for preservation of homeostage of alive organisms

(constancy of the internal medium) ndash entering energy in it since processes of

disintegration are constantly present

Mathematical calculation of change of free energy

G = H ndash Т S where

G - a part of energy of the system which is spent for fulfillment of work

(kjulemole substances)

H -Change in heat contents of the system (enthalpy)

Т - absolute temperature

S - entropy change disorder of the systems

The energy enters animals organism in the form of proteins carbohydrates and

lipids catabolism of which conducts to becoming this energy free and its trans-

formation into

Energy of macroergs (АТP etc)

Electric energy

Thermal energy

Mechanical one

Energy of chemical bonds etc

113

High-energy (macroergs) and low-energy compounds of animals tissue АТP - universal macroergs in plants and animals world

macroergic compounds are called the substances having macroergic bond

macroergic bond is marked by ldquo~rdquo Energy is used for satisfaction of

energy needs of a cell

compound product of reaction -G kjulemole

phosphoenolpyruvate pyruvate + Н3РО4 619

13-bisphosphoglycerate 3-phosphoglycerate+Н3РО4 545

carbamoylphosphate carbamate + Н3РО4 515

creatinephosphate creatine + Н3РО4 431

pyrophosphate Н4Р2О7 2 Н3РО4 334

Acetyle-CoA acetate +HS-CоА 350

Succinyle-CoA succinate + HS-CoA 435

АТP (GTPUTP etc) ADP + Н3РО4 345 (~73 kcalmole)

ADP АМP + Н3РО4 363

АМP adenosine + Н3РО4 96

glycerophosphate glycerine + Н3РО4 92

glucose-6-phosphate glucose + Н3РО4 138

- Universal macroerg is ATP Its molecule serves as a part connecting among them-

selves various kinds of transformation of energy chemical mechanical electric

osmotic and other processes going with release and consumption of energy

- The reasons of release of energy at hydrolysis of macroergic bond (phospho-

anhydtate) of АТP and АDP

Redistribution of electrons on orbits

pH medium (neutral)

Significance of dissociation (АТP-4 АDP-3 АМP-2)

- Daily requirement of the adult for energy (АТP) and real presence АТP in an or-

ganism (˜65kg available 3-4g)

- Reactions n of АDP rephosphorylatio and subsequent use of АТP as an energy

source (dephosphorylation) form the cycle which repeats 25-3 thousand times per day

The diagram of the formation and use of АТP in an organism

Solar energy

plants cells (carbohy-

drates lipids proteins)

feeding of animals

Energy of

Carbohydrates lipids pro-

teins

АТP

АDP + Н3РО4

biosynthesis

Muscular reduction

Active transport of ions

through membranes (po-

tential of rest and potential

of action)

Other volatile processes

energydependent

(body temperature)

re

ph

osp

ho

ryla

tio

n

Dep

ho

sph

ory

latio

n

114

2 modes of ADP rephosphorylation

Oxidative phosphorylation

Substrate phosphorylation

The main substrates for rephosphorylation of АDP oxidation of proteins fats

and carbohydrates in tissues during their oxidation

Variants of oxidation of organic substances in animal tissues

oxidase type (dehydration and transport of electrons and protons on oxy-

gen with the formation of energy Н2О СО2) oxigenase (oxidations of a substrate by oxygen)

mechanisms of peroxide oxidation of lipids

peroxidase type (oxidation of a substrate with the formation of hydrogen

peroxide and use of the latter for oxidation of other substrates)

Oxidase type of oxidations of proteins lipids carbohydrates (cell respiration of

tissues) is the basic mode of oxidation in tissues of animals and at the same time it manu-

factures energy (АТP and heat)

Oxidase type of oxidation of substrates is provided with enzymes and coferments of

the respiratory circuit

Chemical compound of components of a respiratory circuit and their

redox-potential

Components of a respiratory circuit are collected from the set of enzymes and

polypeptides which contain a number of various oxidizing and restored

coferments and cofactors (iron copper) as a prostetic group

Е0В ndash042 ndash 032 + 004 + 007 + 023 + 025 + 029 + 055 + 082

Н NAD (FMN) Ко Q b Fe3+

c1 Fe3+

c Fe3+

a Fe3+

a3 (Cu2+

Fe3+

) 12O2

R

Н NADН2 Ко Q Н2 b Fe2+

c1 Fe2+

c Fe2+

a Fe2+

a3 (Cu+Fe

2+) Н2О

And also Fes protein ATP ATP ATP

cytochromes dehydrogenase

ndash 005

FAD

FADН2

(2)

(1)

115

The redox-potential is characterized by the energy which is released at transporting electrons from the given substance on a hydrogen electrode and is ex-

pressed in electron-volts

o The redox-potential and the function of components of the respiratory circuit depend on a chemical nature and correlation of the oxidized and

restored molecules included in their structure

o Members of oxidation-reduction lines settle down in ascending order of potentials [-032В - (+082В)]

o Components of the respiratory circuit in mitochondria are organized in complexes (the circuit is on page 15)

The respiratory circuit includes four albuminous complexes (I III IV V) built - in the internal mitochondrial membrane and two mobile systems mole-

cules - carriers - ubiquinone (КоQ) and cytochromes C Succinate dehydrogenase from cycle TCA is also considered as well as the complex of II respiratory

circuit

complex I ( NADН-dehydrogenase + FMN +FeS-proteins)

complex II ( succinate dehydrogenase + FAD +FeS-proteins)

complex III (cytochromendashC- reductase contents cytochromes b c1 и FeS-proteins)

complex IV (cytochrome-C- oxidase contents cytochromes а and а3 Сu)

complex V ( АТP-synthase)

electrons and protons enter the respiratory circuit in two ways

in the oxidation of NADН2 complex 1 transfers electrons and protons through FMN and FeS-protein on ubiquinone

in oxidation succinate electrons and protons are transferred on ubiquinone by complex II containing FADН2-dehydrogenase and FeS-protein

As a result in both cases the oxidized form of ubiquinone (КоQ) is restored up to ubihydrochinone (КоQН2)

Then the electrons from КоQН2 are transferred along the circuit by complex III on cytochrome C

cytochrome C transfers electrons to complex IV in which cytochrome а3 has unique properties - ability to transfer electrons on 12О2 with the for-

mation of О-2

ion which joins the protons removed from oxidized substrates through dehydrogenase and KoQ Endogenic water is formed

In the human organism as a result of cell respiration (tissue) 300 - 400 ml of water is formed for a day endogenic or metabolic water (camels in a de-

sert bears - hibernation in a den)

Complete restoration of О2 up to Н2О requires joining 4 е-

In an organism restoration of oxygen occurs stage by stage transferring 1еndash at each stage

Joining the first еndash forms superoxide anion О2

ndash

Joining two еndash forms peroxide anion О2

2ndashН2О2

Peroxide of hydrogen and superoxide radical are very toxic They are destroyed in a cell the first ndash by catalase the second ndash by superoxiddismutase

116

The organization of complexes I-V from the components of the respiratory circuit in mitochondria (scheme)

3 ADP + 3 Pi

Pro

tein

sli

pid

samp c

arb

o-

hydra

tes

of

food

АТP- synthetase

complex V complex I

NADН-dehydrogenase

FMN + FeS - protein

complex III

cytochrome c - reductase (cytochrome bc1)

and FeS - proteins

complex IV

Cytochrome C oxidase

cytochrome аа3 Cu)

КоQ

2е-+2Н

+ e-rarr

e-rarr

cytochrome

С rarre

-rarr

rarre-rarr

Ex

tern

al m

em-

bra

ne

of

mit

o-

cho

ndri

a

Inte

rnal

mem

-b

ran

e of

mit

o-

cho

ndri

a

Intercellular space

4Н2Оharr4 Н++ 4ОН

-

com

ple

x I

I

Su

ccin

ate

deh

yd

rog

enes

is

T C A

Acetyle-CoA

pyru

vat

e

acey

l-C

oA

2Н

++

2е- 4Н2Оharr4 Н

++ 4ОН

-

2Н+

4Н+

2Н

++

2е-

2Н2Оharr2 Н++ 2ОН

-

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

+ + + + + 4Н+ + + + + + + + 2Н

+ +

ОН- ОН

- ОН

-

2Н+

+12О2

12О2

2е-

Н2О

Matrix of

mitochondria

10Н+

10ОН-

10Н2О

3 А

ТP

+

hea

t NADН2

FA

DH

2

Endogenic water

(300-400 ml per day)

О2 + e- О2ˉ (superoxide anion)

О2ˉ+ e- О2

2ˉ (peroxide anion)

О2ˉ +e-+ 2H

+ H2О2 (peroxide of hydrogen)

H2О2+ О2ˉ OHˉ + OH + O2 (hydroxyle

anion and hydroxyle radical)

117

Together with electrons complexes I III and IV due to the energy of electrons

transferring of protons from mitochondrial matrix (Н + are formed at dissocia-

tion of waters) is vectorially made into intermembraneous space where the con-

centration of ions Н+ increases and on a membrane the proton potential Н +

is formed

Biological sense of electrons transport along the respira-tory circuit and transfer of protons into the intermembra-

neous space (chemiosmatic hypothesis of Mitchel -Sculachev)

Transfer of electrons along the respiratory circuit is accompanied with the

gradual releasing energy the part of which (~ 40 ) is used for the formation

of АТP and other energy dissipates as heat (heatproduction)

Energy of electrons is used for the formation of a proton gradient on the inter-

nal mitochondrial membrane The proton potential appears (an electrochemical

gradient of ions Н + Н +)

Formation of АТP (oxidative phosphorylation) entails the reverse stream of

protons from intermembraneous spaces into mitochondrial matrix however the

membrane of mitochondria is impenetrable for protons

In mitochondria only АТP- synthetase (complex V) allows to carry out the re-

verse movement of protons from intermembranal spaces in mitochondrial matrix

and the same enzyme catalyses the formation of АТP ie synthesis АТP entails

the oxidation of substrate and then coferments and cofactors of respiratory cir-

cuit with participation of oxygen Therefore this process (oxidations and phos-

phorylation of АDP with formation of АТP) has received the name of oxidative

phosphorylation

АТP- synthetase consists of two parts the proton channel (13 subunits of pro-

tein) built in the internal membrane of mitochondria and catalyzed structure

acting in mitochondrial matrix (3 α - and 3 szlig-subunits)

Cycle of formation of АТP is divided into 3 phases

Linkage with the enzyme of АDP and Р

Formation of phosphoanhydrate bond between АDP and Р with the

formation of АТP

Releasing of end-products of the reaction (АТP and waters)

Calculation of the energy educed during the transport of electrons along

the respiratory circuit

Change of free energy (G) during the transport of electrons depends only on a

difference of oxidation-reduction potentials of the donor and the acceptor of

electrons in the respiratory circuit

The general value of the energy released at transport of 2е along the respiratory

circuit can be calculated

G0 = - n F E where

118

G0 - change of free standard energy

n- the number of transferred electrons (for example we shall take 2 of them)

F ndash Faraday number = 23062 cal

mole

E ndash Difference of standard potentials of components of the respiratory cir-

cuit giving (-032 volts) and accepting (+ 082 volts) electrons

Transfer of 2 electrons is accompanied with educing

G0 = - 2 23062 [082 ndash (- 032)] = - 526

kcalmole or (237

кjulemole)

- If protons enter the intermembraneous space through complexes I III

and IV 3 molecules АТP and coefficient of phosphorylation (rela-

tion PO)= 3 are formed if protons enter only through complexes II III

and IV 2 molecules АТP and coefficient of phosphorylation (PO)

= 2 are formed where Р ndash is the quantity of the inorganic phosphate in-

cluded in 2 or 3 АТP O- atom of oxygen on which 2 e- are transferred

- The reasons of conjugation oxidation and phosphorylation (oxidative

phosphorylation) are only on 3 or 2 parts of the respiratory circuit

- On other parts the potential difference of the connected redox-systems

(energy) is insufficient for the formation of АТP in these parts energy is

releasing as heat

- Uncouples of oxidative phosphorylation promote an expenditure of

proton potential without АТP-synthetase dissociation of phosphoryla-

tion and respiration is present

- Breath increases

- Phosphorylation is suppressed

- Heat production increases

- Uncouples of respiration and phosphorylations

- thermogenins

- Free fatty acids RCOO-+ Н + (on the external part of the membrane)

RCOOH reg RCOO-+ Н + (on the internal part of the membrane)

- 24-dinitrophenol salicylates (anti-inflammatory remedies)

- Peculiarities of the formation of heat in newborns and animals born

bald and also running into hibernation (brown fat and peculiarities of

their respiratory circuit organization)

- Brown fat in newborns

- They contain more mitochondria

- They have 10 times more enzymes of respiration than phosphorylation

- Presence of thermogenins in the membrane provides dissociation of res-

piration and phosphorylation that leads to formation of a plenty of heat

warming flowing blood

Regulation of energy exchange

For a day the requirement of an organism in energy (АТP) varies

The rate of the АТP formation depends on a energy status of cells iе correla-

tion

[ATP]

[ADP] [P]

119

At rest the energy charge of a cell changes is about 09 and comes nearer to 1

unit

[АТP] + frac12 [АDP]

[АTP] [АDP] + [АMP

At use of energy (АТP) by the organism a part of АТP is hydrolized up to АDP

and Р the enrgy charge of a cell is reduced

Increase of АDP concentration automatically will increase the rate of oxidizing

phosphorylation and the formations АТP ie the respiration of mitochondria is

checked with the help of АDP This mechanism of regulation of energy ex-

change of a cell has got the name ldquothe respiratory controlrdquo - there is no res-

piration if there is no ADP in the cell

Oxidizing mode of substrate oxidation

It is catalysed with mono-and dioxygenase

monoxygenases ndashis including of 1 atom of oxygen into the oxidized

substrate and the other one into the molecule of water according to the

scheme

R RO + H2O

dioxygenases - enzymes which catalyzed the reaction - including of both atoms

of oxygen in to the oxidizing substance

R +О2 RО2

microsomal oxidation is a version of the microsomal mode (enzymes of

oxidation - cytochromes Р450 are in microsomes)

- Bile acids

- - Steroid hormones

- - Heterologous substances (drugs toxins etc)

They are oxidazed according to oxygenase mode without educing energy

H

+ O2

H

RndashН + О2 RndashОН + Н2О

2еoline

NADPН2

FAD

Fe-protein

Р450

2Н+

120

Lipid Peroxidation (LP)

Active oxygen species (НО2- peroxide radical middotО2oline - superoxide radical middotОН-

hydroxyl radical) are capable to take hydrogen away from (-СН2-) the groups of

fatty acids transforming them into (-middotСН-) groups

Such radicals easily join molecules of oxygen and become a peroxyl radical of

fatty acids

ndashmiddotСНndash + О2 ndashСНndashОndashО

middot

The radical chain reaction begins when the peroxyl radical takes a hydrogen at-

om from the other fatty acid molecule thus stimulates free radical chain re-

actions

ndashСНndashОndashОmiddot + (ndashСН2ndash) ndashСНndashОndashОН + (ndash

middotСНndash)

Nonsaturated fatty acids which turn into peroxids and hydroperoxids of li-

pids are most sensitive to Lipid Peroxidation

Products of the LP - hydroperoxids of lipids spirits aldehydes malonic alde-

hyde ketons etc

Biological significance of Lipid Peroxidation

Regulation of renovating and permeability of lipid biological mem-

branes

In phagocytic cells for destruction of the absorbed bacteria and infec-

tious material Н2О2 and a superoxide radical which initiate the LP are

used and bacteria perish

Free radical processes can completely destroy nonsaturated lipids of

biomembranes of host cells causing inevitable destruction of cells

In the membranes of cells free radical processes are limited as there are various systems of protection against active forms of oxygen (antioxidant systems) in

cells

PERIOXIDIZATION MODE

R∙H2 + O2 rarr R + H2O2

Localization in peroxysomas (about 80 of H2O2 are formed) enzymes- ox-

ydase of amino acids amines etc

Biological significance

Amino acids biogenic amines and other organic molecules are oxidized

in such a way

Thus toxic for cells of an organism hydrogen peroxide H2O2 is formed

In leukocytes H2O2 is used for neutralization of pathogenic bacteria

In cells H2O2 is neutralized with the help of enzymes (catalase [E1] peroxydase

[E2])according to the scheme

2Н2О2 2Н2О + О2

Н2О2 + R Н2О + RO

121

Protection of membranes against LP

1 Inactivization of oxygen radicals under the action of superoxide

dismutase and catalase

2 Fermentative mechanism of membrane protection against LP un-

der the action of glutathione peroxidase

3 Chemical protection of membranes against LP with the help of anti-

oxidizers (the most powerful antioxidizer is Vitamin E)

113

High-energy (macroergs) and low-energy compounds of animals tissue АТP - universal macroergs in plants and animals world

macroergic compounds are called the substances having macroergic bond

macroergic bond is marked by ldquo~rdquo Energy is used for satisfaction of

energy needs of a cell

compound product of reaction -G kjulemole

phosphoenolpyruvate pyruvate + Н3РО4 619

13-bisphosphoglycerate 3-phosphoglycerate+Н3РО4 545

carbamoylphosphate carbamate + Н3РО4 515

creatinephosphate creatine + Н3РО4 431

pyrophosphate Н4Р2О7 2 Н3РО4 334

Acetyle-CoA acetate +HS-CоА 350

Succinyle-CoA succinate + HS-CoA 435

АТP (GTPUTP etc) ADP + Н3РО4 345 (~73 kcalmole)

ADP АМP + Н3РО4 363

АМP adenosine + Н3РО4 96

glycerophosphate glycerine + Н3РО4 92

glucose-6-phosphate glucose + Н3РО4 138

- Universal macroerg is ATP Its molecule serves as a part connecting among them-

selves various kinds of transformation of energy chemical mechanical electric

osmotic and other processes going with release and consumption of energy

- The reasons of release of energy at hydrolysis of macroergic bond (phospho-

anhydtate) of АТP and АDP

Redistribution of electrons on orbits

pH medium (neutral)

Significance of dissociation (АТP-4 АDP-3 АМP-2)

- Daily requirement of the adult for energy (АТP) and real presence АТP in an or-

ganism (˜65kg available 3-4g)

- Reactions n of АDP rephosphorylatio and subsequent use of АТP as an energy

source (dephosphorylation) form the cycle which repeats 25-3 thousand times per day

The diagram of the formation and use of АТP in an organism

Solar energy

plants cells (carbohy-

drates lipids proteins)

feeding of animals

Energy of

Carbohydrates lipids pro-

teins

АТP

АDP + Н3РО4

biosynthesis

Muscular reduction

Active transport of ions

through membranes (po-

tential of rest and potential

of action)

Other volatile processes

energydependent

(body temperature)

re

ph

osp

ho

ryla

tio

n

Dep

ho

sph

ory

latio

n

114

2 modes of ADP rephosphorylation

Oxidative phosphorylation

Substrate phosphorylation

The main substrates for rephosphorylation of АDP oxidation of proteins fats

and carbohydrates in tissues during their oxidation

Variants of oxidation of organic substances in animal tissues

oxidase type (dehydration and transport of electrons and protons on oxy-

gen with the formation of energy Н2О СО2) oxigenase (oxidations of a substrate by oxygen)

mechanisms of peroxide oxidation of lipids

peroxidase type (oxidation of a substrate with the formation of hydrogen

peroxide and use of the latter for oxidation of other substrates)

Oxidase type of oxidations of proteins lipids carbohydrates (cell respiration of

tissues) is the basic mode of oxidation in tissues of animals and at the same time it manu-

factures energy (АТP and heat)

Oxidase type of oxidation of substrates is provided with enzymes and coferments of

the respiratory circuit

Chemical compound of components of a respiratory circuit and their

redox-potential

Components of a respiratory circuit are collected from the set of enzymes and

polypeptides which contain a number of various oxidizing and restored

coferments and cofactors (iron copper) as a prostetic group

Е0В ndash042 ndash 032 + 004 + 007 + 023 + 025 + 029 + 055 + 082

Н NAD (FMN) Ко Q b Fe3+

c1 Fe3+

c Fe3+

a Fe3+

a3 (Cu2+

Fe3+

) 12O2

R

Н NADН2 Ко Q Н2 b Fe2+

c1 Fe2+

c Fe2+

a Fe2+

a3 (Cu+Fe

2+) Н2О

And also Fes protein ATP ATP ATP

cytochromes dehydrogenase

ndash 005

FAD

FADН2

(2)

(1)

115

The redox-potential is characterized by the energy which is released at transporting electrons from the given substance on a hydrogen electrode and is ex-

pressed in electron-volts

o The redox-potential and the function of components of the respiratory circuit depend on a chemical nature and correlation of the oxidized and

restored molecules included in their structure

o Members of oxidation-reduction lines settle down in ascending order of potentials [-032В - (+082В)]

o Components of the respiratory circuit in mitochondria are organized in complexes (the circuit is on page 15)

The respiratory circuit includes four albuminous complexes (I III IV V) built - in the internal mitochondrial membrane and two mobile systems mole-

cules - carriers - ubiquinone (КоQ) and cytochromes C Succinate dehydrogenase from cycle TCA is also considered as well as the complex of II respiratory

circuit

complex I ( NADН-dehydrogenase + FMN +FeS-proteins)

complex II ( succinate dehydrogenase + FAD +FeS-proteins)

complex III (cytochromendashC- reductase contents cytochromes b c1 и FeS-proteins)

complex IV (cytochrome-C- oxidase contents cytochromes а and а3 Сu)

complex V ( АТP-synthase)

electrons and protons enter the respiratory circuit in two ways

in the oxidation of NADН2 complex 1 transfers electrons and protons through FMN and FeS-protein on ubiquinone

in oxidation succinate electrons and protons are transferred on ubiquinone by complex II containing FADН2-dehydrogenase and FeS-protein

As a result in both cases the oxidized form of ubiquinone (КоQ) is restored up to ubihydrochinone (КоQН2)

Then the electrons from КоQН2 are transferred along the circuit by complex III on cytochrome C

cytochrome C transfers electrons to complex IV in which cytochrome а3 has unique properties - ability to transfer electrons on 12О2 with the for-

mation of О-2

ion which joins the protons removed from oxidized substrates through dehydrogenase and KoQ Endogenic water is formed

In the human organism as a result of cell respiration (tissue) 300 - 400 ml of water is formed for a day endogenic or metabolic water (camels in a de-

sert bears - hibernation in a den)

Complete restoration of О2 up to Н2О requires joining 4 е-

In an organism restoration of oxygen occurs stage by stage transferring 1еndash at each stage

Joining the first еndash forms superoxide anion О2

ndash

Joining two еndash forms peroxide anion О2

2ndashН2О2

Peroxide of hydrogen and superoxide radical are very toxic They are destroyed in a cell the first ndash by catalase the second ndash by superoxiddismutase

116

The organization of complexes I-V from the components of the respiratory circuit in mitochondria (scheme)

3 ADP + 3 Pi

Pro

tein

sli

pid

samp c

arb

o-

hydra

tes

of

food

АТP- synthetase

complex V complex I

NADН-dehydrogenase

FMN + FeS - protein

complex III

cytochrome c - reductase (cytochrome bc1)

and FeS - proteins

complex IV

Cytochrome C oxidase

cytochrome аа3 Cu)

КоQ

2е-+2Н

+ e-rarr

e-rarr

cytochrome

С rarre

-rarr

rarre-rarr

Ex

tern

al m

em-

bra

ne

of

mit

o-

cho

ndri

a

Inte

rnal

mem

-b

ran

e of

mit

o-

cho

ndri

a

Intercellular space

4Н2Оharr4 Н++ 4ОН

-

com

ple

x I

I

Su

ccin

ate

deh

yd

rog

enes

is

T C A

Acetyle-CoA

pyru

vat

e

acey

l-C

oA

2Н

++

2е- 4Н2Оharr4 Н

++ 4ОН

-

2Н+

4Н+

2Н

++

2е-

2Н2Оharr2 Н++ 2ОН

-

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

+ + + + + 4Н+ + + + + + + + 2Н

+ +

ОН- ОН

- ОН

-

2Н+

+12О2

12О2

2е-

Н2О

Matrix of

mitochondria

10Н+

10ОН-

10Н2О

3 А

ТP

+

hea

t NADН2

FA

DH

2

Endogenic water

(300-400 ml per day)

О2 + e- О2ˉ (superoxide anion)

О2ˉ+ e- О2

2ˉ (peroxide anion)

О2ˉ +e-+ 2H

+ H2О2 (peroxide of hydrogen)

H2О2+ О2ˉ OHˉ + OH + O2 (hydroxyle

anion and hydroxyle radical)

117

Together with electrons complexes I III and IV due to the energy of electrons

transferring of protons from mitochondrial matrix (Н + are formed at dissocia-

tion of waters) is vectorially made into intermembraneous space where the con-

centration of ions Н+ increases and on a membrane the proton potential Н +

is formed

Biological sense of electrons transport along the respira-tory circuit and transfer of protons into the intermembra-

neous space (chemiosmatic hypothesis of Mitchel -Sculachev)

Transfer of electrons along the respiratory circuit is accompanied with the

gradual releasing energy the part of which (~ 40 ) is used for the formation

of АТP and other energy dissipates as heat (heatproduction)

Energy of electrons is used for the formation of a proton gradient on the inter-

nal mitochondrial membrane The proton potential appears (an electrochemical

gradient of ions Н + Н +)

Formation of АТP (oxidative phosphorylation) entails the reverse stream of

protons from intermembraneous spaces into mitochondrial matrix however the

membrane of mitochondria is impenetrable for protons

In mitochondria only АТP- synthetase (complex V) allows to carry out the re-

verse movement of protons from intermembranal spaces in mitochondrial matrix

and the same enzyme catalyses the formation of АТP ie synthesis АТP entails

the oxidation of substrate and then coferments and cofactors of respiratory cir-

cuit with participation of oxygen Therefore this process (oxidations and phos-

phorylation of АDP with formation of АТP) has received the name of oxidative

phosphorylation

АТP- synthetase consists of two parts the proton channel (13 subunits of pro-

tein) built in the internal membrane of mitochondria and catalyzed structure

acting in mitochondrial matrix (3 α - and 3 szlig-subunits)

Cycle of formation of АТP is divided into 3 phases

Linkage with the enzyme of АDP and Р

Formation of phosphoanhydrate bond between АDP and Р with the

formation of АТP

Releasing of end-products of the reaction (АТP and waters)

Calculation of the energy educed during the transport of electrons along

the respiratory circuit

Change of free energy (G) during the transport of electrons depends only on a

difference of oxidation-reduction potentials of the donor and the acceptor of

electrons in the respiratory circuit

The general value of the energy released at transport of 2е along the respiratory

circuit can be calculated

G0 = - n F E where

118

G0 - change of free standard energy

n- the number of transferred electrons (for example we shall take 2 of them)

F ndash Faraday number = 23062 cal

mole

E ndash Difference of standard potentials of components of the respiratory cir-

cuit giving (-032 volts) and accepting (+ 082 volts) electrons

Transfer of 2 electrons is accompanied with educing

G0 = - 2 23062 [082 ndash (- 032)] = - 526

kcalmole or (237

кjulemole)

- If protons enter the intermembraneous space through complexes I III

and IV 3 molecules АТP and coefficient of phosphorylation (rela-

tion PO)= 3 are formed if protons enter only through complexes II III

and IV 2 molecules АТP and coefficient of phosphorylation (PO)

= 2 are formed where Р ndash is the quantity of the inorganic phosphate in-

cluded in 2 or 3 АТP O- atom of oxygen on which 2 e- are transferred

- The reasons of conjugation oxidation and phosphorylation (oxidative

phosphorylation) are only on 3 or 2 parts of the respiratory circuit

- On other parts the potential difference of the connected redox-systems

(energy) is insufficient for the formation of АТP in these parts energy is

releasing as heat

- Uncouples of oxidative phosphorylation promote an expenditure of

proton potential without АТP-synthetase dissociation of phosphoryla-

tion and respiration is present

- Breath increases

- Phosphorylation is suppressed

- Heat production increases

- Uncouples of respiration and phosphorylations

- thermogenins

- Free fatty acids RCOO-+ Н + (on the external part of the membrane)

RCOOH reg RCOO-+ Н + (on the internal part of the membrane)

- 24-dinitrophenol salicylates (anti-inflammatory remedies)

- Peculiarities of the formation of heat in newborns and animals born

bald and also running into hibernation (brown fat and peculiarities of

their respiratory circuit organization)

- Brown fat in newborns

- They contain more mitochondria

- They have 10 times more enzymes of respiration than phosphorylation

- Presence of thermogenins in the membrane provides dissociation of res-

piration and phosphorylation that leads to formation of a plenty of heat

warming flowing blood

Regulation of energy exchange

For a day the requirement of an organism in energy (АТP) varies

The rate of the АТP formation depends on a energy status of cells iе correla-

tion

[ATP]

[ADP] [P]

119

At rest the energy charge of a cell changes is about 09 and comes nearer to 1

unit

[АТP] + frac12 [АDP]

[АTP] [АDP] + [АMP

At use of energy (АТP) by the organism a part of АТP is hydrolized up to АDP

and Р the enrgy charge of a cell is reduced

Increase of АDP concentration automatically will increase the rate of oxidizing

phosphorylation and the formations АТP ie the respiration of mitochondria is

checked with the help of АDP This mechanism of regulation of energy ex-

change of a cell has got the name ldquothe respiratory controlrdquo - there is no res-

piration if there is no ADP in the cell

Oxidizing mode of substrate oxidation

It is catalysed with mono-and dioxygenase

monoxygenases ndashis including of 1 atom of oxygen into the oxidized

substrate and the other one into the molecule of water according to the

scheme

R RO + H2O

dioxygenases - enzymes which catalyzed the reaction - including of both atoms

of oxygen in to the oxidizing substance

R +О2 RО2

microsomal oxidation is a version of the microsomal mode (enzymes of

oxidation - cytochromes Р450 are in microsomes)

- Bile acids

- - Steroid hormones

- - Heterologous substances (drugs toxins etc)

They are oxidazed according to oxygenase mode without educing energy

H

+ O2

H

RndashН + О2 RndashОН + Н2О

2еoline

NADPН2

FAD

Fe-protein

Р450

2Н+

120

Lipid Peroxidation (LP)

Active oxygen species (НО2- peroxide radical middotО2oline - superoxide radical middotОН-

hydroxyl radical) are capable to take hydrogen away from (-СН2-) the groups of

fatty acids transforming them into (-middotСН-) groups

Such radicals easily join molecules of oxygen and become a peroxyl radical of

fatty acids

ndashmiddotСНndash + О2 ndashСНndashОndashО

middot

The radical chain reaction begins when the peroxyl radical takes a hydrogen at-

om from the other fatty acid molecule thus stimulates free radical chain re-

actions

ndashСНndashОndashОmiddot + (ndashСН2ndash) ndashСНndashОndashОН + (ndash

middotСНndash)

Nonsaturated fatty acids which turn into peroxids and hydroperoxids of li-

pids are most sensitive to Lipid Peroxidation

Products of the LP - hydroperoxids of lipids spirits aldehydes malonic alde-

hyde ketons etc

Biological significance of Lipid Peroxidation

Regulation of renovating and permeability of lipid biological mem-

branes

In phagocytic cells for destruction of the absorbed bacteria and infec-

tious material Н2О2 and a superoxide radical which initiate the LP are

used and bacteria perish

Free radical processes can completely destroy nonsaturated lipids of

biomembranes of host cells causing inevitable destruction of cells

In the membranes of cells free radical processes are limited as there are various systems of protection against active forms of oxygen (antioxidant systems) in

cells

PERIOXIDIZATION MODE

R∙H2 + O2 rarr R + H2O2

Localization in peroxysomas (about 80 of H2O2 are formed) enzymes- ox-

ydase of amino acids amines etc

Biological significance

Amino acids biogenic amines and other organic molecules are oxidized

in such a way

Thus toxic for cells of an organism hydrogen peroxide H2O2 is formed

In leukocytes H2O2 is used for neutralization of pathogenic bacteria

In cells H2O2 is neutralized with the help of enzymes (catalase [E1] peroxydase

[E2])according to the scheme

2Н2О2 2Н2О + О2

Н2О2 + R Н2О + RO

121

Protection of membranes against LP

1 Inactivization of oxygen radicals under the action of superoxide

dismutase and catalase

2 Fermentative mechanism of membrane protection against LP un-

der the action of glutathione peroxidase

3 Chemical protection of membranes against LP with the help of anti-

oxidizers (the most powerful antioxidizer is Vitamin E)

114

2 modes of ADP rephosphorylation

Oxidative phosphorylation

Substrate phosphorylation

The main substrates for rephosphorylation of АDP oxidation of proteins fats

and carbohydrates in tissues during their oxidation

Variants of oxidation of organic substances in animal tissues

oxidase type (dehydration and transport of electrons and protons on oxy-

gen with the formation of energy Н2О СО2) oxigenase (oxidations of a substrate by oxygen)

mechanisms of peroxide oxidation of lipids

peroxidase type (oxidation of a substrate with the formation of hydrogen

peroxide and use of the latter for oxidation of other substrates)

Oxidase type of oxidations of proteins lipids carbohydrates (cell respiration of

tissues) is the basic mode of oxidation in tissues of animals and at the same time it manu-

factures energy (АТP and heat)

Oxidase type of oxidation of substrates is provided with enzymes and coferments of

the respiratory circuit

Chemical compound of components of a respiratory circuit and their

redox-potential

Components of a respiratory circuit are collected from the set of enzymes and

polypeptides which contain a number of various oxidizing and restored

coferments and cofactors (iron copper) as a prostetic group

Е0В ndash042 ndash 032 + 004 + 007 + 023 + 025 + 029 + 055 + 082

Н NAD (FMN) Ко Q b Fe3+

c1 Fe3+

c Fe3+

a Fe3+

a3 (Cu2+

Fe3+

) 12O2

R

Н NADН2 Ко Q Н2 b Fe2+

c1 Fe2+

c Fe2+

a Fe2+

a3 (Cu+Fe

2+) Н2О

And also Fes protein ATP ATP ATP

cytochromes dehydrogenase

ndash 005

FAD

FADН2

(2)

(1)

115

The redox-potential is characterized by the energy which is released at transporting electrons from the given substance on a hydrogen electrode and is ex-

pressed in electron-volts

o The redox-potential and the function of components of the respiratory circuit depend on a chemical nature and correlation of the oxidized and

restored molecules included in their structure

o Members of oxidation-reduction lines settle down in ascending order of potentials [-032В - (+082В)]

o Components of the respiratory circuit in mitochondria are organized in complexes (the circuit is on page 15)

The respiratory circuit includes four albuminous complexes (I III IV V) built - in the internal mitochondrial membrane and two mobile systems mole-

cules - carriers - ubiquinone (КоQ) and cytochromes C Succinate dehydrogenase from cycle TCA is also considered as well as the complex of II respiratory

circuit

complex I ( NADН-dehydrogenase + FMN +FeS-proteins)

complex II ( succinate dehydrogenase + FAD +FeS-proteins)

complex III (cytochromendashC- reductase contents cytochromes b c1 и FeS-proteins)

complex IV (cytochrome-C- oxidase contents cytochromes а and а3 Сu)

complex V ( АТP-synthase)

electrons and protons enter the respiratory circuit in two ways

in the oxidation of NADН2 complex 1 transfers electrons and protons through FMN and FeS-protein on ubiquinone

in oxidation succinate electrons and protons are transferred on ubiquinone by complex II containing FADН2-dehydrogenase and FeS-protein

As a result in both cases the oxidized form of ubiquinone (КоQ) is restored up to ubihydrochinone (КоQН2)

Then the electrons from КоQН2 are transferred along the circuit by complex III on cytochrome C

cytochrome C transfers electrons to complex IV in which cytochrome а3 has unique properties - ability to transfer electrons on 12О2 with the for-

mation of О-2

ion which joins the protons removed from oxidized substrates through dehydrogenase and KoQ Endogenic water is formed

In the human organism as a result of cell respiration (tissue) 300 - 400 ml of water is formed for a day endogenic or metabolic water (camels in a de-

sert bears - hibernation in a den)

Complete restoration of О2 up to Н2О requires joining 4 е-

In an organism restoration of oxygen occurs stage by stage transferring 1еndash at each stage

Joining the first еndash forms superoxide anion О2

ndash

Joining two еndash forms peroxide anion О2

2ndashН2О2

Peroxide of hydrogen and superoxide radical are very toxic They are destroyed in a cell the first ndash by catalase the second ndash by superoxiddismutase

116

The organization of complexes I-V from the components of the respiratory circuit in mitochondria (scheme)

3 ADP + 3 Pi

Pro

tein

sli

pid

samp c

arb

o-

hydra

tes

of

food

АТP- synthetase

complex V complex I

NADН-dehydrogenase

FMN + FeS - protein

complex III

cytochrome c - reductase (cytochrome bc1)

and FeS - proteins

complex IV

Cytochrome C oxidase

cytochrome аа3 Cu)

КоQ

2е-+2Н

+ e-rarr

e-rarr

cytochrome

С rarre

-rarr

rarre-rarr

Ex

tern

al m

em-

bra

ne

of

mit

o-

cho

ndri

a

Inte

rnal

mem

-b

ran

e of

mit

o-

cho

ndri

a

Intercellular space

4Н2Оharr4 Н++ 4ОН

-

com

ple

x I

I

Su

ccin

ate

deh

yd

rog

enes

is

T C A

Acetyle-CoA

pyru

vat

e

acey

l-C

oA

2Н

++

2е- 4Н2Оharr4 Н

++ 4ОН

-

2Н+

4Н+

2Н

++

2е-

2Н2Оharr2 Н++ 2ОН

-

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

+ + + + + 4Н+ + + + + + + + 2Н

+ +

ОН- ОН

- ОН

-

2Н+

+12О2

12О2

2е-

Н2О

Matrix of

mitochondria

10Н+

10ОН-

10Н2О

3 А

ТP

+

hea

t NADН2

FA

DH

2

Endogenic water

(300-400 ml per day)

О2 + e- О2ˉ (superoxide anion)

О2ˉ+ e- О2

2ˉ (peroxide anion)

О2ˉ +e-+ 2H

+ H2О2 (peroxide of hydrogen)

H2О2+ О2ˉ OHˉ + OH + O2 (hydroxyle

anion and hydroxyle radical)

117

Together with electrons complexes I III and IV due to the energy of electrons

transferring of protons from mitochondrial matrix (Н + are formed at dissocia-

tion of waters) is vectorially made into intermembraneous space where the con-

centration of ions Н+ increases and on a membrane the proton potential Н +

is formed

Biological sense of electrons transport along the respira-tory circuit and transfer of protons into the intermembra-

neous space (chemiosmatic hypothesis of Mitchel -Sculachev)

Transfer of electrons along the respiratory circuit is accompanied with the

gradual releasing energy the part of which (~ 40 ) is used for the formation

of АТP and other energy dissipates as heat (heatproduction)

Energy of electrons is used for the formation of a proton gradient on the inter-

nal mitochondrial membrane The proton potential appears (an electrochemical

gradient of ions Н + Н +)

Formation of АТP (oxidative phosphorylation) entails the reverse stream of

protons from intermembraneous spaces into mitochondrial matrix however the

membrane of mitochondria is impenetrable for protons

In mitochondria only АТP- synthetase (complex V) allows to carry out the re-

verse movement of protons from intermembranal spaces in mitochondrial matrix

and the same enzyme catalyses the formation of АТP ie synthesis АТP entails

the oxidation of substrate and then coferments and cofactors of respiratory cir-

cuit with participation of oxygen Therefore this process (oxidations and phos-

phorylation of АDP with formation of АТP) has received the name of oxidative

phosphorylation

АТP- synthetase consists of two parts the proton channel (13 subunits of pro-

tein) built in the internal membrane of mitochondria and catalyzed structure

acting in mitochondrial matrix (3 α - and 3 szlig-subunits)

Cycle of formation of АТP is divided into 3 phases

Linkage with the enzyme of АDP and Р

Formation of phosphoanhydrate bond between АDP and Р with the

formation of АТP

Releasing of end-products of the reaction (АТP and waters)

Calculation of the energy educed during the transport of electrons along

the respiratory circuit

Change of free energy (G) during the transport of electrons depends only on a

difference of oxidation-reduction potentials of the donor and the acceptor of

electrons in the respiratory circuit

The general value of the energy released at transport of 2е along the respiratory

circuit can be calculated

G0 = - n F E where

118

G0 - change of free standard energy

n- the number of transferred electrons (for example we shall take 2 of them)

F ndash Faraday number = 23062 cal

mole

E ndash Difference of standard potentials of components of the respiratory cir-

cuit giving (-032 volts) and accepting (+ 082 volts) electrons

Transfer of 2 electrons is accompanied with educing

G0 = - 2 23062 [082 ndash (- 032)] = - 526

kcalmole or (237

кjulemole)

- If protons enter the intermembraneous space through complexes I III

and IV 3 molecules АТP and coefficient of phosphorylation (rela-

tion PO)= 3 are formed if protons enter only through complexes II III

and IV 2 molecules АТP and coefficient of phosphorylation (PO)

= 2 are formed where Р ndash is the quantity of the inorganic phosphate in-

cluded in 2 or 3 АТP O- atom of oxygen on which 2 e- are transferred

- The reasons of conjugation oxidation and phosphorylation (oxidative

phosphorylation) are only on 3 or 2 parts of the respiratory circuit

- On other parts the potential difference of the connected redox-systems

(energy) is insufficient for the formation of АТP in these parts energy is

releasing as heat

- Uncouples of oxidative phosphorylation promote an expenditure of

proton potential without АТP-synthetase dissociation of phosphoryla-

tion and respiration is present

- Breath increases

- Phosphorylation is suppressed

- Heat production increases

- Uncouples of respiration and phosphorylations

- thermogenins

- Free fatty acids RCOO-+ Н + (on the external part of the membrane)

RCOOH reg RCOO-+ Н + (on the internal part of the membrane)

- 24-dinitrophenol salicylates (anti-inflammatory remedies)

- Peculiarities of the formation of heat in newborns and animals born

bald and also running into hibernation (brown fat and peculiarities of

their respiratory circuit organization)

- Brown fat in newborns

- They contain more mitochondria

- They have 10 times more enzymes of respiration than phosphorylation

- Presence of thermogenins in the membrane provides dissociation of res-

piration and phosphorylation that leads to formation of a plenty of heat

warming flowing blood

Regulation of energy exchange

For a day the requirement of an organism in energy (АТP) varies

The rate of the АТP formation depends on a energy status of cells iе correla-

tion

[ATP]

[ADP] [P]

119

At rest the energy charge of a cell changes is about 09 and comes nearer to 1

unit

[АТP] + frac12 [АDP]

[АTP] [АDP] + [АMP

At use of energy (АТP) by the organism a part of АТP is hydrolized up to АDP

and Р the enrgy charge of a cell is reduced

Increase of АDP concentration automatically will increase the rate of oxidizing

phosphorylation and the formations АТP ie the respiration of mitochondria is

checked with the help of АDP This mechanism of regulation of energy ex-

change of a cell has got the name ldquothe respiratory controlrdquo - there is no res-

piration if there is no ADP in the cell

Oxidizing mode of substrate oxidation

It is catalysed with mono-and dioxygenase

monoxygenases ndashis including of 1 atom of oxygen into the oxidized

substrate and the other one into the molecule of water according to the

scheme

R RO + H2O

dioxygenases - enzymes which catalyzed the reaction - including of both atoms

of oxygen in to the oxidizing substance

R +О2 RО2

microsomal oxidation is a version of the microsomal mode (enzymes of

oxidation - cytochromes Р450 are in microsomes)

- Bile acids

- - Steroid hormones

- - Heterologous substances (drugs toxins etc)

They are oxidazed according to oxygenase mode without educing energy

H

+ O2

H

RndashН + О2 RndashОН + Н2О

2еoline

NADPН2

FAD

Fe-protein

Р450

2Н+

120

Lipid Peroxidation (LP)

Active oxygen species (НО2- peroxide radical middotО2oline - superoxide radical middotОН-

hydroxyl radical) are capable to take hydrogen away from (-СН2-) the groups of

fatty acids transforming them into (-middotСН-) groups

Such radicals easily join molecules of oxygen and become a peroxyl radical of

fatty acids

ndashmiddotСНndash + О2 ndashСНndashОndashО

middot

The radical chain reaction begins when the peroxyl radical takes a hydrogen at-

om from the other fatty acid molecule thus stimulates free radical chain re-

actions

ndashСНndashОndashОmiddot + (ndashСН2ndash) ndashСНndashОndashОН + (ndash

middotСНndash)

Nonsaturated fatty acids which turn into peroxids and hydroperoxids of li-

pids are most sensitive to Lipid Peroxidation

Products of the LP - hydroperoxids of lipids spirits aldehydes malonic alde-

hyde ketons etc

Biological significance of Lipid Peroxidation

Regulation of renovating and permeability of lipid biological mem-

branes

In phagocytic cells for destruction of the absorbed bacteria and infec-

tious material Н2О2 and a superoxide radical which initiate the LP are

used and bacteria perish

Free radical processes can completely destroy nonsaturated lipids of

biomembranes of host cells causing inevitable destruction of cells

In the membranes of cells free radical processes are limited as there are various systems of protection against active forms of oxygen (antioxidant systems) in

cells

PERIOXIDIZATION MODE

R∙H2 + O2 rarr R + H2O2

Localization in peroxysomas (about 80 of H2O2 are formed) enzymes- ox-

ydase of amino acids amines etc

Biological significance

Amino acids biogenic amines and other organic molecules are oxidized

in such a way

Thus toxic for cells of an organism hydrogen peroxide H2O2 is formed

In leukocytes H2O2 is used for neutralization of pathogenic bacteria

In cells H2O2 is neutralized with the help of enzymes (catalase [E1] peroxydase

[E2])according to the scheme

2Н2О2 2Н2О + О2

Н2О2 + R Н2О + RO

121

Protection of membranes against LP

1 Inactivization of oxygen radicals under the action of superoxide

dismutase and catalase

2 Fermentative mechanism of membrane protection against LP un-

der the action of glutathione peroxidase

3 Chemical protection of membranes against LP with the help of anti-

oxidizers (the most powerful antioxidizer is Vitamin E)

115

The redox-potential is characterized by the energy which is released at transporting electrons from the given substance on a hydrogen electrode and is ex-

pressed in electron-volts

o The redox-potential and the function of components of the respiratory circuit depend on a chemical nature and correlation of the oxidized and

restored molecules included in their structure

o Members of oxidation-reduction lines settle down in ascending order of potentials [-032В - (+082В)]

o Components of the respiratory circuit in mitochondria are organized in complexes (the circuit is on page 15)

The respiratory circuit includes four albuminous complexes (I III IV V) built - in the internal mitochondrial membrane and two mobile systems mole-

cules - carriers - ubiquinone (КоQ) and cytochromes C Succinate dehydrogenase from cycle TCA is also considered as well as the complex of II respiratory

circuit

complex I ( NADН-dehydrogenase + FMN +FeS-proteins)

complex II ( succinate dehydrogenase + FAD +FeS-proteins)

complex III (cytochromendashC- reductase contents cytochromes b c1 и FeS-proteins)

complex IV (cytochrome-C- oxidase contents cytochromes а and а3 Сu)

complex V ( АТP-synthase)

electrons and protons enter the respiratory circuit in two ways

in the oxidation of NADН2 complex 1 transfers electrons and protons through FMN and FeS-protein on ubiquinone

in oxidation succinate electrons and protons are transferred on ubiquinone by complex II containing FADН2-dehydrogenase and FeS-protein

As a result in both cases the oxidized form of ubiquinone (КоQ) is restored up to ubihydrochinone (КоQН2)

Then the electrons from КоQН2 are transferred along the circuit by complex III on cytochrome C

cytochrome C transfers electrons to complex IV in which cytochrome а3 has unique properties - ability to transfer electrons on 12О2 with the for-

mation of О-2

ion which joins the protons removed from oxidized substrates through dehydrogenase and KoQ Endogenic water is formed

In the human organism as a result of cell respiration (tissue) 300 - 400 ml of water is formed for a day endogenic or metabolic water (camels in a de-

sert bears - hibernation in a den)

Complete restoration of О2 up to Н2О requires joining 4 е-

In an organism restoration of oxygen occurs stage by stage transferring 1еndash at each stage

Joining the first еndash forms superoxide anion О2

ndash

Joining two еndash forms peroxide anion О2

2ndashН2О2

Peroxide of hydrogen and superoxide radical are very toxic They are destroyed in a cell the first ndash by catalase the second ndash by superoxiddismutase

116

The organization of complexes I-V from the components of the respiratory circuit in mitochondria (scheme)

3 ADP + 3 Pi

Pro

tein

sli

pid

samp c

arb

o-

hydra

tes

of

food

АТP- synthetase

complex V complex I

NADН-dehydrogenase

FMN + FeS - protein

complex III

cytochrome c - reductase (cytochrome bc1)

and FeS - proteins

complex IV

Cytochrome C oxidase

cytochrome аа3 Cu)

КоQ

2е-+2Н

+ e-rarr

e-rarr

cytochrome

С rarre

-rarr

rarre-rarr

Ex

tern

al m

em-

bra

ne

of

mit

o-

cho

ndri

a

Inte

rnal

mem

-b

ran

e of

mit

o-

cho

ndri

a

Intercellular space

4Н2Оharr4 Н++ 4ОН

-

com

ple

x I

I

Su

ccin

ate

deh

yd

rog

enes

is

T C A

Acetyle-CoA

pyru

vat

e

acey

l-C

oA

2Н

++

2е- 4Н2Оharr4 Н

++ 4ОН

-

2Н+

4Н+

2Н

++

2е-

2Н2Оharr2 Н++ 2ОН

-

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

+ + + + + 4Н+ + + + + + + + 2Н

+ +

ОН- ОН

- ОН

-

2Н+

+12О2

12О2

2е-

Н2О

Matrix of

mitochondria

10Н+

10ОН-

10Н2О

3 А

ТP

+

hea

t NADН2

FA

DH

2

Endogenic water

(300-400 ml per day)

О2 + e- О2ˉ (superoxide anion)

О2ˉ+ e- О2

2ˉ (peroxide anion)

О2ˉ +e-+ 2H

+ H2О2 (peroxide of hydrogen)

H2О2+ О2ˉ OHˉ + OH + O2 (hydroxyle

anion and hydroxyle radical)

117

Together with electrons complexes I III and IV due to the energy of electrons

transferring of protons from mitochondrial matrix (Н + are formed at dissocia-

tion of waters) is vectorially made into intermembraneous space where the con-

centration of ions Н+ increases and on a membrane the proton potential Н +

is formed

Biological sense of electrons transport along the respira-tory circuit and transfer of protons into the intermembra-

neous space (chemiosmatic hypothesis of Mitchel -Sculachev)

Transfer of electrons along the respiratory circuit is accompanied with the

gradual releasing energy the part of which (~ 40 ) is used for the formation

of АТP and other energy dissipates as heat (heatproduction)

Energy of electrons is used for the formation of a proton gradient on the inter-

nal mitochondrial membrane The proton potential appears (an electrochemical

gradient of ions Н + Н +)

Formation of АТP (oxidative phosphorylation) entails the reverse stream of

protons from intermembraneous spaces into mitochondrial matrix however the

membrane of mitochondria is impenetrable for protons

In mitochondria only АТP- synthetase (complex V) allows to carry out the re-

verse movement of protons from intermembranal spaces in mitochondrial matrix

and the same enzyme catalyses the formation of АТP ie synthesis АТP entails

the oxidation of substrate and then coferments and cofactors of respiratory cir-

cuit with participation of oxygen Therefore this process (oxidations and phos-

phorylation of АDP with formation of АТP) has received the name of oxidative

phosphorylation

АТP- synthetase consists of two parts the proton channel (13 subunits of pro-

tein) built in the internal membrane of mitochondria and catalyzed structure

acting in mitochondrial matrix (3 α - and 3 szlig-subunits)

Cycle of formation of АТP is divided into 3 phases

Linkage with the enzyme of АDP and Р

Formation of phosphoanhydrate bond between АDP and Р with the

formation of АТP

Releasing of end-products of the reaction (АТP and waters)

Calculation of the energy educed during the transport of electrons along

the respiratory circuit

Change of free energy (G) during the transport of electrons depends only on a

difference of oxidation-reduction potentials of the donor and the acceptor of

electrons in the respiratory circuit

The general value of the energy released at transport of 2е along the respiratory

circuit can be calculated

G0 = - n F E where

118

G0 - change of free standard energy

n- the number of transferred electrons (for example we shall take 2 of them)

F ndash Faraday number = 23062 cal

mole

E ndash Difference of standard potentials of components of the respiratory cir-

cuit giving (-032 volts) and accepting (+ 082 volts) electrons

Transfer of 2 electrons is accompanied with educing

G0 = - 2 23062 [082 ndash (- 032)] = - 526

kcalmole or (237

кjulemole)

- If protons enter the intermembraneous space through complexes I III

and IV 3 molecules АТP and coefficient of phosphorylation (rela-

tion PO)= 3 are formed if protons enter only through complexes II III

and IV 2 molecules АТP and coefficient of phosphorylation (PO)

= 2 are formed where Р ndash is the quantity of the inorganic phosphate in-

cluded in 2 or 3 АТP O- atom of oxygen on which 2 e- are transferred

- The reasons of conjugation oxidation and phosphorylation (oxidative

phosphorylation) are only on 3 or 2 parts of the respiratory circuit

- On other parts the potential difference of the connected redox-systems

(energy) is insufficient for the formation of АТP in these parts energy is

releasing as heat

- Uncouples of oxidative phosphorylation promote an expenditure of

proton potential without АТP-synthetase dissociation of phosphoryla-

tion and respiration is present

- Breath increases

- Phosphorylation is suppressed

- Heat production increases

- Uncouples of respiration and phosphorylations

- thermogenins

- Free fatty acids RCOO-+ Н + (on the external part of the membrane)

RCOOH reg RCOO-+ Н + (on the internal part of the membrane)

- 24-dinitrophenol salicylates (anti-inflammatory remedies)

- Peculiarities of the formation of heat in newborns and animals born

bald and also running into hibernation (brown fat and peculiarities of

their respiratory circuit organization)

- Brown fat in newborns

- They contain more mitochondria

- They have 10 times more enzymes of respiration than phosphorylation

- Presence of thermogenins in the membrane provides dissociation of res-

piration and phosphorylation that leads to formation of a plenty of heat

warming flowing blood

Regulation of energy exchange

For a day the requirement of an organism in energy (АТP) varies

The rate of the АТP formation depends on a energy status of cells iе correla-

tion

[ATP]

[ADP] [P]

119

At rest the energy charge of a cell changes is about 09 and comes nearer to 1

unit

[АТP] + frac12 [АDP]

[АTP] [АDP] + [АMP

At use of energy (АТP) by the organism a part of АТP is hydrolized up to АDP

and Р the enrgy charge of a cell is reduced

Increase of АDP concentration automatically will increase the rate of oxidizing

phosphorylation and the formations АТP ie the respiration of mitochondria is

checked with the help of АDP This mechanism of regulation of energy ex-

change of a cell has got the name ldquothe respiratory controlrdquo - there is no res-

piration if there is no ADP in the cell

Oxidizing mode of substrate oxidation

It is catalysed with mono-and dioxygenase

monoxygenases ndashis including of 1 atom of oxygen into the oxidized

substrate and the other one into the molecule of water according to the

scheme

R RO + H2O

dioxygenases - enzymes which catalyzed the reaction - including of both atoms

of oxygen in to the oxidizing substance

R +О2 RО2

microsomal oxidation is a version of the microsomal mode (enzymes of

oxidation - cytochromes Р450 are in microsomes)

- Bile acids

- - Steroid hormones

- - Heterologous substances (drugs toxins etc)

They are oxidazed according to oxygenase mode without educing energy

H

+ O2

H

RndashН + О2 RndashОН + Н2О

2еoline

NADPН2

FAD

Fe-protein

Р450

2Н+

120

Lipid Peroxidation (LP)

Active oxygen species (НО2- peroxide radical middotО2oline - superoxide radical middotОН-

hydroxyl radical) are capable to take hydrogen away from (-СН2-) the groups of

fatty acids transforming them into (-middotСН-) groups

Such radicals easily join molecules of oxygen and become a peroxyl radical of

fatty acids

ndashmiddotСНndash + О2 ndashСНndashОndashО

middot

The radical chain reaction begins when the peroxyl radical takes a hydrogen at-

om from the other fatty acid molecule thus stimulates free radical chain re-

actions

ndashСНndashОndashОmiddot + (ndashСН2ndash) ndashСНndashОndashОН + (ndash

middotСНndash)

Nonsaturated fatty acids which turn into peroxids and hydroperoxids of li-

pids are most sensitive to Lipid Peroxidation

Products of the LP - hydroperoxids of lipids spirits aldehydes malonic alde-

hyde ketons etc

Biological significance of Lipid Peroxidation

Regulation of renovating and permeability of lipid biological mem-

branes

In phagocytic cells for destruction of the absorbed bacteria and infec-

tious material Н2О2 and a superoxide radical which initiate the LP are

used and bacteria perish

Free radical processes can completely destroy nonsaturated lipids of

biomembranes of host cells causing inevitable destruction of cells

In the membranes of cells free radical processes are limited as there are various systems of protection against active forms of oxygen (antioxidant systems) in

cells

PERIOXIDIZATION MODE

R∙H2 + O2 rarr R + H2O2

Localization in peroxysomas (about 80 of H2O2 are formed) enzymes- ox-

ydase of amino acids amines etc

Biological significance

Amino acids biogenic amines and other organic molecules are oxidized

in such a way

Thus toxic for cells of an organism hydrogen peroxide H2O2 is formed

In leukocytes H2O2 is used for neutralization of pathogenic bacteria

In cells H2O2 is neutralized with the help of enzymes (catalase [E1] peroxydase

[E2])according to the scheme

2Н2О2 2Н2О + О2

Н2О2 + R Н2О + RO

121

Protection of membranes against LP

1 Inactivization of oxygen radicals under the action of superoxide

dismutase and catalase

2 Fermentative mechanism of membrane protection against LP un-

der the action of glutathione peroxidase

3 Chemical protection of membranes against LP with the help of anti-

oxidizers (the most powerful antioxidizer is Vitamin E)

116

The organization of complexes I-V from the components of the respiratory circuit in mitochondria (scheme)

3 ADP + 3 Pi

Pro

tein

sli

pid

samp c

arb

o-

hydra

tes

of

food

АТP- synthetase

complex V complex I

NADН-dehydrogenase

FMN + FeS - protein

complex III

cytochrome c - reductase (cytochrome bc1)

and FeS - proteins

complex IV

Cytochrome C oxidase

cytochrome аа3 Cu)

КоQ

2е-+2Н

+ e-rarr

e-rarr

cytochrome

С rarre

-rarr

rarre-rarr

Ex

tern

al m

em-

bra

ne

of

mit

o-

cho

ndri

a

Inte

rnal

mem

-b

ran

e of

mit

o-

cho

ndri

a

Intercellular space

4Н2Оharr4 Н++ 4ОН

-

com

ple

x I

I

Su

ccin

ate

deh

yd

rog

enes

is

T C A

Acetyle-CoA

pyru

vat

e

acey

l-C

oA

2Н

++

2е- 4Н2Оharr4 Н

++ 4ОН

-

2Н+

4Н+

2Н

++

2е-

2Н2Оharr2 Н++ 2ОН

-

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

+ + + + + 4Н+ + + + + + + + 2Н

+ +

ОН- ОН

- ОН

-

2Н+

+12О2

12О2

2е-

Н2О

Matrix of

mitochondria

10Н+

10ОН-

10Н2О

3 А

ТP

+

hea

t NADН2

FA

DH

2

Endogenic water

(300-400 ml per day)

О2 + e- О2ˉ (superoxide anion)

О2ˉ+ e- О2

2ˉ (peroxide anion)

О2ˉ +e-+ 2H

+ H2О2 (peroxide of hydrogen)

H2О2+ О2ˉ OHˉ + OH + O2 (hydroxyle

anion and hydroxyle radical)

117

Together with electrons complexes I III and IV due to the energy of electrons

transferring of protons from mitochondrial matrix (Н + are formed at dissocia-

tion of waters) is vectorially made into intermembraneous space where the con-

centration of ions Н+ increases and on a membrane the proton potential Н +

is formed

Biological sense of electrons transport along the respira-tory circuit and transfer of protons into the intermembra-

neous space (chemiosmatic hypothesis of Mitchel -Sculachev)

Transfer of electrons along the respiratory circuit is accompanied with the

gradual releasing energy the part of which (~ 40 ) is used for the formation

of АТP and other energy dissipates as heat (heatproduction)

Energy of electrons is used for the formation of a proton gradient on the inter-

nal mitochondrial membrane The proton potential appears (an electrochemical

gradient of ions Н + Н +)

Formation of АТP (oxidative phosphorylation) entails the reverse stream of

protons from intermembraneous spaces into mitochondrial matrix however the

membrane of mitochondria is impenetrable for protons

In mitochondria only АТP- synthetase (complex V) allows to carry out the re-

verse movement of protons from intermembranal spaces in mitochondrial matrix

and the same enzyme catalyses the formation of АТP ie synthesis АТP entails

the oxidation of substrate and then coferments and cofactors of respiratory cir-

cuit with participation of oxygen Therefore this process (oxidations and phos-

phorylation of АDP with formation of АТP) has received the name of oxidative

phosphorylation

АТP- synthetase consists of two parts the proton channel (13 subunits of pro-

tein) built in the internal membrane of mitochondria and catalyzed structure

acting in mitochondrial matrix (3 α - and 3 szlig-subunits)

Cycle of formation of АТP is divided into 3 phases

Linkage with the enzyme of АDP and Р

Formation of phosphoanhydrate bond between АDP and Р with the

formation of АТP

Releasing of end-products of the reaction (АТP and waters)

Calculation of the energy educed during the transport of electrons along

the respiratory circuit

Change of free energy (G) during the transport of electrons depends only on a

difference of oxidation-reduction potentials of the donor and the acceptor of

electrons in the respiratory circuit

The general value of the energy released at transport of 2е along the respiratory

circuit can be calculated

G0 = - n F E where

118

G0 - change of free standard energy

n- the number of transferred electrons (for example we shall take 2 of them)

F ndash Faraday number = 23062 cal

mole

E ndash Difference of standard potentials of components of the respiratory cir-

cuit giving (-032 volts) and accepting (+ 082 volts) electrons

Transfer of 2 electrons is accompanied with educing

G0 = - 2 23062 [082 ndash (- 032)] = - 526

kcalmole or (237

кjulemole)

- If protons enter the intermembraneous space through complexes I III

and IV 3 molecules АТP and coefficient of phosphorylation (rela-

tion PO)= 3 are formed if protons enter only through complexes II III

and IV 2 molecules АТP and coefficient of phosphorylation (PO)

= 2 are formed where Р ndash is the quantity of the inorganic phosphate in-

cluded in 2 or 3 АТP O- atom of oxygen on which 2 e- are transferred

- The reasons of conjugation oxidation and phosphorylation (oxidative

phosphorylation) are only on 3 or 2 parts of the respiratory circuit

- On other parts the potential difference of the connected redox-systems

(energy) is insufficient for the formation of АТP in these parts energy is

releasing as heat

- Uncouples of oxidative phosphorylation promote an expenditure of

proton potential without АТP-synthetase dissociation of phosphoryla-

tion and respiration is present

- Breath increases

- Phosphorylation is suppressed

- Heat production increases

- Uncouples of respiration and phosphorylations

- thermogenins

- Free fatty acids RCOO-+ Н + (on the external part of the membrane)

RCOOH reg RCOO-+ Н + (on the internal part of the membrane)

- 24-dinitrophenol salicylates (anti-inflammatory remedies)

- Peculiarities of the formation of heat in newborns and animals born

bald and also running into hibernation (brown fat and peculiarities of

their respiratory circuit organization)

- Brown fat in newborns

- They contain more mitochondria

- They have 10 times more enzymes of respiration than phosphorylation

- Presence of thermogenins in the membrane provides dissociation of res-

piration and phosphorylation that leads to formation of a plenty of heat

warming flowing blood

Regulation of energy exchange

For a day the requirement of an organism in energy (АТP) varies

The rate of the АТP formation depends on a energy status of cells iе correla-

tion

[ATP]

[ADP] [P]

119

At rest the energy charge of a cell changes is about 09 and comes nearer to 1

unit

[АТP] + frac12 [АDP]

[АTP] [АDP] + [АMP

At use of energy (АТP) by the organism a part of АТP is hydrolized up to АDP

and Р the enrgy charge of a cell is reduced

Increase of АDP concentration automatically will increase the rate of oxidizing

phosphorylation and the formations АТP ie the respiration of mitochondria is

checked with the help of АDP This mechanism of regulation of energy ex-

change of a cell has got the name ldquothe respiratory controlrdquo - there is no res-

piration if there is no ADP in the cell

Oxidizing mode of substrate oxidation

It is catalysed with mono-and dioxygenase

monoxygenases ndashis including of 1 atom of oxygen into the oxidized

substrate and the other one into the molecule of water according to the

scheme

R RO + H2O

dioxygenases - enzymes which catalyzed the reaction - including of both atoms

of oxygen in to the oxidizing substance

R +О2 RО2

microsomal oxidation is a version of the microsomal mode (enzymes of

oxidation - cytochromes Р450 are in microsomes)

- Bile acids

- - Steroid hormones

- - Heterologous substances (drugs toxins etc)

They are oxidazed according to oxygenase mode without educing energy

H

+ O2

H

RndashН + О2 RndashОН + Н2О

2еoline

NADPН2

FAD

Fe-protein

Р450

2Н+

120

Lipid Peroxidation (LP)

Active oxygen species (НО2- peroxide radical middotО2oline - superoxide radical middotОН-

hydroxyl radical) are capable to take hydrogen away from (-СН2-) the groups of

fatty acids transforming them into (-middotСН-) groups

Such radicals easily join molecules of oxygen and become a peroxyl radical of

fatty acids

ndashmiddotСНndash + О2 ndashСНndashОndashО

middot

The radical chain reaction begins when the peroxyl radical takes a hydrogen at-

om from the other fatty acid molecule thus stimulates free radical chain re-

actions

ndashСНndashОndashОmiddot + (ndashСН2ndash) ndashСНndashОndashОН + (ndash

middotСНndash)

Nonsaturated fatty acids which turn into peroxids and hydroperoxids of li-

pids are most sensitive to Lipid Peroxidation

Products of the LP - hydroperoxids of lipids spirits aldehydes malonic alde-

hyde ketons etc

Biological significance of Lipid Peroxidation

Regulation of renovating and permeability of lipid biological mem-

branes

In phagocytic cells for destruction of the absorbed bacteria and infec-

tious material Н2О2 and a superoxide radical which initiate the LP are

used and bacteria perish

Free radical processes can completely destroy nonsaturated lipids of

biomembranes of host cells causing inevitable destruction of cells

In the membranes of cells free radical processes are limited as there are various systems of protection against active forms of oxygen (antioxidant systems) in

cells

PERIOXIDIZATION MODE

R∙H2 + O2 rarr R + H2O2

Localization in peroxysomas (about 80 of H2O2 are formed) enzymes- ox-

ydase of amino acids amines etc

Biological significance

Amino acids biogenic amines and other organic molecules are oxidized

in such a way

Thus toxic for cells of an organism hydrogen peroxide H2O2 is formed

In leukocytes H2O2 is used for neutralization of pathogenic bacteria

In cells H2O2 is neutralized with the help of enzymes (catalase [E1] peroxydase

[E2])according to the scheme

2Н2О2 2Н2О + О2

Н2О2 + R Н2О + RO

121

Protection of membranes against LP

1 Inactivization of oxygen radicals under the action of superoxide

dismutase and catalase

2 Fermentative mechanism of membrane protection against LP un-

der the action of glutathione peroxidase

3 Chemical protection of membranes against LP with the help of anti-

oxidizers (the most powerful antioxidizer is Vitamin E)

117

Together with electrons complexes I III and IV due to the energy of electrons

transferring of protons from mitochondrial matrix (Н + are formed at dissocia-

tion of waters) is vectorially made into intermembraneous space where the con-

centration of ions Н+ increases and on a membrane the proton potential Н +

is formed

Biological sense of electrons transport along the respira-tory circuit and transfer of protons into the intermembra-

neous space (chemiosmatic hypothesis of Mitchel -Sculachev)

Transfer of electrons along the respiratory circuit is accompanied with the

gradual releasing energy the part of which (~ 40 ) is used for the formation

of АТP and other energy dissipates as heat (heatproduction)

Energy of electrons is used for the formation of a proton gradient on the inter-

nal mitochondrial membrane The proton potential appears (an electrochemical

gradient of ions Н + Н +)

Formation of АТP (oxidative phosphorylation) entails the reverse stream of

protons from intermembraneous spaces into mitochondrial matrix however the

membrane of mitochondria is impenetrable for protons

In mitochondria only АТP- synthetase (complex V) allows to carry out the re-

verse movement of protons from intermembranal spaces in mitochondrial matrix

and the same enzyme catalyses the formation of АТP ie synthesis АТP entails

the oxidation of substrate and then coferments and cofactors of respiratory cir-

cuit with participation of oxygen Therefore this process (oxidations and phos-

phorylation of АDP with formation of АТP) has received the name of oxidative

phosphorylation

АТP- synthetase consists of two parts the proton channel (13 subunits of pro-

tein) built in the internal membrane of mitochondria and catalyzed structure

acting in mitochondrial matrix (3 α - and 3 szlig-subunits)

Cycle of formation of АТP is divided into 3 phases

Linkage with the enzyme of АDP and Р

Formation of phosphoanhydrate bond between АDP and Р with the

formation of АТP

Releasing of end-products of the reaction (АТP and waters)

Calculation of the energy educed during the transport of electrons along

the respiratory circuit

Change of free energy (G) during the transport of electrons depends only on a

difference of oxidation-reduction potentials of the donor and the acceptor of

electrons in the respiratory circuit

The general value of the energy released at transport of 2е along the respiratory

circuit can be calculated

G0 = - n F E where

118

G0 - change of free standard energy

n- the number of transferred electrons (for example we shall take 2 of them)

F ndash Faraday number = 23062 cal

mole

E ndash Difference of standard potentials of components of the respiratory cir-

cuit giving (-032 volts) and accepting (+ 082 volts) electrons

Transfer of 2 electrons is accompanied with educing

G0 = - 2 23062 [082 ndash (- 032)] = - 526

kcalmole or (237

кjulemole)

- If protons enter the intermembraneous space through complexes I III

and IV 3 molecules АТP and coefficient of phosphorylation (rela-

tion PO)= 3 are formed if protons enter only through complexes II III

and IV 2 molecules АТP and coefficient of phosphorylation (PO)

= 2 are formed where Р ndash is the quantity of the inorganic phosphate in-

cluded in 2 or 3 АТP O- atom of oxygen on which 2 e- are transferred

- The reasons of conjugation oxidation and phosphorylation (oxidative

phosphorylation) are only on 3 or 2 parts of the respiratory circuit

- On other parts the potential difference of the connected redox-systems

(energy) is insufficient for the formation of АТP in these parts energy is

releasing as heat

- Uncouples of oxidative phosphorylation promote an expenditure of

proton potential without АТP-synthetase dissociation of phosphoryla-

tion and respiration is present

- Breath increases

- Phosphorylation is suppressed

- Heat production increases

- Uncouples of respiration and phosphorylations

- thermogenins

- Free fatty acids RCOO-+ Н + (on the external part of the membrane)

RCOOH reg RCOO-+ Н + (on the internal part of the membrane)

- 24-dinitrophenol salicylates (anti-inflammatory remedies)

- Peculiarities of the formation of heat in newborns and animals born

bald and also running into hibernation (brown fat and peculiarities of

their respiratory circuit organization)

- Brown fat in newborns

- They contain more mitochondria

- They have 10 times more enzymes of respiration than phosphorylation

- Presence of thermogenins in the membrane provides dissociation of res-

piration and phosphorylation that leads to formation of a plenty of heat

warming flowing blood

Regulation of energy exchange

For a day the requirement of an organism in energy (АТP) varies

The rate of the АТP formation depends on a energy status of cells iе correla-

tion

[ATP]

[ADP] [P]

119

At rest the energy charge of a cell changes is about 09 and comes nearer to 1

unit

[АТP] + frac12 [АDP]

[АTP] [АDP] + [АMP

At use of energy (АТP) by the organism a part of АТP is hydrolized up to АDP

and Р the enrgy charge of a cell is reduced

Increase of АDP concentration automatically will increase the rate of oxidizing

phosphorylation and the formations АТP ie the respiration of mitochondria is

checked with the help of АDP This mechanism of regulation of energy ex-

change of a cell has got the name ldquothe respiratory controlrdquo - there is no res-

piration if there is no ADP in the cell

Oxidizing mode of substrate oxidation

It is catalysed with mono-and dioxygenase

monoxygenases ndashis including of 1 atom of oxygen into the oxidized

substrate and the other one into the molecule of water according to the

scheme

R RO + H2O

dioxygenases - enzymes which catalyzed the reaction - including of both atoms

of oxygen in to the oxidizing substance

R +О2 RО2

microsomal oxidation is a version of the microsomal mode (enzymes of

oxidation - cytochromes Р450 are in microsomes)

- Bile acids

- - Steroid hormones

- - Heterologous substances (drugs toxins etc)

They are oxidazed according to oxygenase mode without educing energy

H

+ O2

H

RndashН + О2 RndashОН + Н2О

2еoline

NADPН2

FAD

Fe-protein

Р450

2Н+

120

Lipid Peroxidation (LP)

Active oxygen species (НО2- peroxide radical middotО2oline - superoxide radical middotОН-

hydroxyl radical) are capable to take hydrogen away from (-СН2-) the groups of

fatty acids transforming them into (-middotСН-) groups

Such radicals easily join molecules of oxygen and become a peroxyl radical of

fatty acids

ndashmiddotСНndash + О2 ndashСНndashОndashО

middot

The radical chain reaction begins when the peroxyl radical takes a hydrogen at-

om from the other fatty acid molecule thus stimulates free radical chain re-

actions

ndashСНndashОndashОmiddot + (ndashСН2ndash) ndashСНndashОndashОН + (ndash

middotСНndash)

Nonsaturated fatty acids which turn into peroxids and hydroperoxids of li-

pids are most sensitive to Lipid Peroxidation

Products of the LP - hydroperoxids of lipids spirits aldehydes malonic alde-

hyde ketons etc

Biological significance of Lipid Peroxidation

Regulation of renovating and permeability of lipid biological mem-

branes

In phagocytic cells for destruction of the absorbed bacteria and infec-

tious material Н2О2 and a superoxide radical which initiate the LP are

used and bacteria perish

Free radical processes can completely destroy nonsaturated lipids of

biomembranes of host cells causing inevitable destruction of cells

In the membranes of cells free radical processes are limited as there are various systems of protection against active forms of oxygen (antioxidant systems) in

cells

PERIOXIDIZATION MODE

R∙H2 + O2 rarr R + H2O2

Localization in peroxysomas (about 80 of H2O2 are formed) enzymes- ox-

ydase of amino acids amines etc

Biological significance

Amino acids biogenic amines and other organic molecules are oxidized

in such a way

Thus toxic for cells of an organism hydrogen peroxide H2O2 is formed

In leukocytes H2O2 is used for neutralization of pathogenic bacteria

In cells H2O2 is neutralized with the help of enzymes (catalase [E1] peroxydase

[E2])according to the scheme

2Н2О2 2Н2О + О2

Н2О2 + R Н2О + RO

121

Protection of membranes against LP

1 Inactivization of oxygen radicals under the action of superoxide

dismutase and catalase

2 Fermentative mechanism of membrane protection against LP un-

der the action of glutathione peroxidase

3 Chemical protection of membranes against LP with the help of anti-

oxidizers (the most powerful antioxidizer is Vitamin E)

118

G0 - change of free standard energy

n- the number of transferred electrons (for example we shall take 2 of them)

F ndash Faraday number = 23062 cal

mole

E ndash Difference of standard potentials of components of the respiratory cir-

cuit giving (-032 volts) and accepting (+ 082 volts) electrons

Transfer of 2 electrons is accompanied with educing

G0 = - 2 23062 [082 ndash (- 032)] = - 526

kcalmole or (237

кjulemole)

- If protons enter the intermembraneous space through complexes I III

and IV 3 molecules АТP and coefficient of phosphorylation (rela-

tion PO)= 3 are formed if protons enter only through complexes II III

and IV 2 molecules АТP and coefficient of phosphorylation (PO)

= 2 are formed where Р ndash is the quantity of the inorganic phosphate in-

cluded in 2 or 3 АТP O- atom of oxygen on which 2 e- are transferred

- The reasons of conjugation oxidation and phosphorylation (oxidative

phosphorylation) are only on 3 or 2 parts of the respiratory circuit

- On other parts the potential difference of the connected redox-systems

(energy) is insufficient for the formation of АТP in these parts energy is

releasing as heat

- Uncouples of oxidative phosphorylation promote an expenditure of

proton potential without АТP-synthetase dissociation of phosphoryla-

tion and respiration is present

- Breath increases

- Phosphorylation is suppressed

- Heat production increases

- Uncouples of respiration and phosphorylations

- thermogenins

- Free fatty acids RCOO-+ Н + (on the external part of the membrane)

RCOOH reg RCOO-+ Н + (on the internal part of the membrane)

- 24-dinitrophenol salicylates (anti-inflammatory remedies)

- Peculiarities of the formation of heat in newborns and animals born

bald and also running into hibernation (brown fat and peculiarities of

their respiratory circuit organization)

- Brown fat in newborns

- They contain more mitochondria

- They have 10 times more enzymes of respiration than phosphorylation

- Presence of thermogenins in the membrane provides dissociation of res-

piration and phosphorylation that leads to formation of a plenty of heat

warming flowing blood

Regulation of energy exchange

For a day the requirement of an organism in energy (АТP) varies

The rate of the АТP formation depends on a energy status of cells iе correla-

tion

[ATP]

[ADP] [P]

119

At rest the energy charge of a cell changes is about 09 and comes nearer to 1

unit

[АТP] + frac12 [АDP]

[АTP] [АDP] + [АMP

At use of energy (АТP) by the organism a part of АТP is hydrolized up to АDP

and Р the enrgy charge of a cell is reduced

Increase of АDP concentration automatically will increase the rate of oxidizing

phosphorylation and the formations АТP ie the respiration of mitochondria is

checked with the help of АDP This mechanism of regulation of energy ex-

change of a cell has got the name ldquothe respiratory controlrdquo - there is no res-

piration if there is no ADP in the cell

Oxidizing mode of substrate oxidation

It is catalysed with mono-and dioxygenase

monoxygenases ndashis including of 1 atom of oxygen into the oxidized

substrate and the other one into the molecule of water according to the

scheme

R RO + H2O

dioxygenases - enzymes which catalyzed the reaction - including of both atoms

of oxygen in to the oxidizing substance

R +О2 RО2

microsomal oxidation is a version of the microsomal mode (enzymes of

oxidation - cytochromes Р450 are in microsomes)

- Bile acids

- - Steroid hormones

- - Heterologous substances (drugs toxins etc)

They are oxidazed according to oxygenase mode without educing energy

H

+ O2

H

RndashН + О2 RndashОН + Н2О

2еoline

NADPН2

FAD

Fe-protein

Р450

2Н+

120

Lipid Peroxidation (LP)

Active oxygen species (НО2- peroxide radical middotО2oline - superoxide radical middotОН-

hydroxyl radical) are capable to take hydrogen away from (-СН2-) the groups of

fatty acids transforming them into (-middotСН-) groups

Such radicals easily join molecules of oxygen and become a peroxyl radical of

fatty acids

ndashmiddotСНndash + О2 ndashСНndashОndashО

middot

The radical chain reaction begins when the peroxyl radical takes a hydrogen at-

om from the other fatty acid molecule thus stimulates free radical chain re-

actions

ndashСНndashОndashОmiddot + (ndashСН2ndash) ndashСНndashОndashОН + (ndash

middotСНndash)

Nonsaturated fatty acids which turn into peroxids and hydroperoxids of li-

pids are most sensitive to Lipid Peroxidation

Products of the LP - hydroperoxids of lipids spirits aldehydes malonic alde-

hyde ketons etc

Biological significance of Lipid Peroxidation

Regulation of renovating and permeability of lipid biological mem-

branes

In phagocytic cells for destruction of the absorbed bacteria and infec-

tious material Н2О2 and a superoxide radical which initiate the LP are

used and bacteria perish

Free radical processes can completely destroy nonsaturated lipids of

biomembranes of host cells causing inevitable destruction of cells

In the membranes of cells free radical processes are limited as there are various systems of protection against active forms of oxygen (antioxidant systems) in

cells

PERIOXIDIZATION MODE

R∙H2 + O2 rarr R + H2O2

Localization in peroxysomas (about 80 of H2O2 are formed) enzymes- ox-

ydase of amino acids amines etc

Biological significance

Amino acids biogenic amines and other organic molecules are oxidized

in such a way

Thus toxic for cells of an organism hydrogen peroxide H2O2 is formed

In leukocytes H2O2 is used for neutralization of pathogenic bacteria

In cells H2O2 is neutralized with the help of enzymes (catalase [E1] peroxydase

[E2])according to the scheme

2Н2О2 2Н2О + О2

Н2О2 + R Н2О + RO

121

Protection of membranes against LP

1 Inactivization of oxygen radicals under the action of superoxide

dismutase and catalase

2 Fermentative mechanism of membrane protection against LP un-

der the action of glutathione peroxidase

3 Chemical protection of membranes against LP with the help of anti-

oxidizers (the most powerful antioxidizer is Vitamin E)

119

At rest the energy charge of a cell changes is about 09 and comes nearer to 1

unit

[АТP] + frac12 [АDP]

[АTP] [АDP] + [АMP

At use of energy (АТP) by the organism a part of АТP is hydrolized up to АDP

and Р the enrgy charge of a cell is reduced

Increase of АDP concentration automatically will increase the rate of oxidizing

phosphorylation and the formations АТP ie the respiration of mitochondria is

checked with the help of АDP This mechanism of regulation of energy ex-

change of a cell has got the name ldquothe respiratory controlrdquo - there is no res-

piration if there is no ADP in the cell

Oxidizing mode of substrate oxidation

It is catalysed with mono-and dioxygenase

monoxygenases ndashis including of 1 atom of oxygen into the oxidized

substrate and the other one into the molecule of water according to the

scheme

R RO + H2O

dioxygenases - enzymes which catalyzed the reaction - including of both atoms

of oxygen in to the oxidizing substance

R +О2 RО2

microsomal oxidation is a version of the microsomal mode (enzymes of

oxidation - cytochromes Р450 are in microsomes)

- Bile acids

- - Steroid hormones

- - Heterologous substances (drugs toxins etc)

They are oxidazed according to oxygenase mode without educing energy

H

+ O2

H

RndashН + О2 RndashОН + Н2О

2еoline

NADPН2

FAD

Fe-protein

Р450

2Н+

120

Lipid Peroxidation (LP)

Active oxygen species (НО2- peroxide radical middotО2oline - superoxide radical middotОН-

hydroxyl radical) are capable to take hydrogen away from (-СН2-) the groups of

fatty acids transforming them into (-middotСН-) groups

Such radicals easily join molecules of oxygen and become a peroxyl radical of

fatty acids

ndashmiddotСНndash + О2 ndashСНndashОndashО

middot

The radical chain reaction begins when the peroxyl radical takes a hydrogen at-

om from the other fatty acid molecule thus stimulates free radical chain re-

actions

ndashСНndashОndashОmiddot + (ndashСН2ndash) ndashСНndashОndashОН + (ndash

middotСНndash)

Nonsaturated fatty acids which turn into peroxids and hydroperoxids of li-

pids are most sensitive to Lipid Peroxidation

Products of the LP - hydroperoxids of lipids spirits aldehydes malonic alde-

hyde ketons etc

Biological significance of Lipid Peroxidation

Regulation of renovating and permeability of lipid biological mem-

branes

In phagocytic cells for destruction of the absorbed bacteria and infec-

tious material Н2О2 and a superoxide radical which initiate the LP are

used and bacteria perish

Free radical processes can completely destroy nonsaturated lipids of

biomembranes of host cells causing inevitable destruction of cells

In the membranes of cells free radical processes are limited as there are various systems of protection against active forms of oxygen (antioxidant systems) in

cells

PERIOXIDIZATION MODE

R∙H2 + O2 rarr R + H2O2

Localization in peroxysomas (about 80 of H2O2 are formed) enzymes- ox-

ydase of amino acids amines etc

Biological significance

Amino acids biogenic amines and other organic molecules are oxidized

in such a way

Thus toxic for cells of an organism hydrogen peroxide H2O2 is formed

In leukocytes H2O2 is used for neutralization of pathogenic bacteria

In cells H2O2 is neutralized with the help of enzymes (catalase [E1] peroxydase

[E2])according to the scheme

2Н2О2 2Н2О + О2

Н2О2 + R Н2О + RO

121

Protection of membranes against LP

1 Inactivization of oxygen radicals under the action of superoxide

dismutase and catalase

2 Fermentative mechanism of membrane protection against LP un-

der the action of glutathione peroxidase

3 Chemical protection of membranes against LP with the help of anti-

oxidizers (the most powerful antioxidizer is Vitamin E)

120

Lipid Peroxidation (LP)

Active oxygen species (НО2- peroxide radical middotО2oline - superoxide radical middotОН-

hydroxyl radical) are capable to take hydrogen away from (-СН2-) the groups of

fatty acids transforming them into (-middotСН-) groups

Such radicals easily join molecules of oxygen and become a peroxyl radical of

fatty acids

ndashmiddotСНndash + О2 ndashСНndashОndashО

middot

The radical chain reaction begins when the peroxyl radical takes a hydrogen at-

om from the other fatty acid molecule thus stimulates free radical chain re-

actions

ndashСНndashОndashОmiddot + (ndashСН2ndash) ndashСНndashОndashОН + (ndash

middotСНndash)

Nonsaturated fatty acids which turn into peroxids and hydroperoxids of li-

pids are most sensitive to Lipid Peroxidation

Products of the LP - hydroperoxids of lipids spirits aldehydes malonic alde-

hyde ketons etc

Biological significance of Lipid Peroxidation

Regulation of renovating and permeability of lipid biological mem-

branes

In phagocytic cells for destruction of the absorbed bacteria and infec-

tious material Н2О2 and a superoxide radical which initiate the LP are

used and bacteria perish

Free radical processes can completely destroy nonsaturated lipids of

biomembranes of host cells causing inevitable destruction of cells

In the membranes of cells free radical processes are limited as there are various systems of protection against active forms of oxygen (antioxidant systems) in

cells

PERIOXIDIZATION MODE

R∙H2 + O2 rarr R + H2O2

Localization in peroxysomas (about 80 of H2O2 are formed) enzymes- ox-

ydase of amino acids amines etc

Biological significance

Amino acids biogenic amines and other organic molecules are oxidized

in such a way

Thus toxic for cells of an organism hydrogen peroxide H2O2 is formed

In leukocytes H2O2 is used for neutralization of pathogenic bacteria

In cells H2O2 is neutralized with the help of enzymes (catalase [E1] peroxydase

[E2])according to the scheme

2Н2О2 2Н2О + О2

Н2О2 + R Н2О + RO

121

Protection of membranes against LP

1 Inactivization of oxygen radicals under the action of superoxide

dismutase and catalase

2 Fermentative mechanism of membrane protection against LP un-

der the action of glutathione peroxidase

3 Chemical protection of membranes against LP with the help of anti-

oxidizers (the most powerful antioxidizer is Vitamin E)

121

Protection of membranes against LP

1 Inactivization of oxygen radicals under the action of superoxide

dismutase and catalase

2 Fermentative mechanism of membrane protection against LP un-

der the action of glutathione peroxidase

3 Chemical protection of membranes against LP with the help of anti-

oxidizers (the most powerful antioxidizer is Vitamin E)