microbial metabolismfaculty.collin.edu/mweis/microbiology/lecture/adobe... · 2005-09-23 ·...
TRANSCRIPT
Microbial Metabolism
Biochemical diversity
Metabolism
DefineRequirements
EnergyEnzymes
RateLimiting stepReaction time
TypesAnabolic
EndergonicDehydration
CatabolicExergonicHydrolytic
Metabolism Relationships
Metabolic Diversity
Energy generating metabolismFermentation
AlcoholAcid Formation
Lactic AcidMixed AcidsOthers
RespirationAerobicAnaerobic
Biosynthesis of secondary metabolitesHeterotrophicAutotrophic
Energy
FormsKineticPotential
UseChemicalMechanicalElectricalRadiation [EM]
Chemical TypesATPUTPGTP
Heat Byproduct45%
Various Types of Prokaryotic Energy Production Processes
FermentationAnaerobic RespirationAerobic RespirationLithotrophyPhotohetertrophyAnoxygenic photosynthesisMethanogenesis
Enzymes
StructureProteinRibozyme [ribosome]
Characteristic functions
Active siteSpecificModified Forms
InactiveActive
Coenzyme/Cofactor-ase
Polymerase
Others: Lyases, Hydrolases,Isomerases, Transferases
Enzyme Characteristics
Enzyme StructureApoenzyme
ProteinAllosteric site
CofactorMetal ions
CuZnMgFeCa
CoenzymeVitaminsCoANADFADFMN
Create Holoenzyme with active site
Allosteric site
Factors Affecting Enzymes
TemperaturepHAcids/basesUV lightConcentration of substrates
Enzyme Inhibition
Noncompetitive atAllosteric siteCompetitive
at active siteExcitatoryInhibitoryReversible
Irreversible
Glycolysis: Embden-Meyerhoff
GlycolyticCytoplasmAnaerobicEnd products
2 Pyruvic acids4-2 = 2 net ATP2 NADH2 H20
Lactic Acid Formation
Glycolysis: PPP
Breakdown 5-6 CCytoplasmAnaerobicEnd products
ATPNADPHCO24,5,6,7 C
AANucleotidesGlycolytic pathwaysPhotosynthesis
Glycolysis: Entner-Duodoroff [E-D]
GlycolyticCytoplasmAnaerobicDifferent enzymes
PseudomonasEnterococcus
End products2-1 = 1 net ATPNADPHNADH2 Pyruvic acids2H20
Glycolytic Pathways used by various Bacteria
Bacterium E-M PPP E-D
Acetobacter aceti - + -
Bacillus subtilis major minor -
E. coli + - -
Lactobacillus acidophilus
+ - -
Pseudomonas aeruginosa
- - +
Vibrio cholera minor - major
Anaerobic Processes
Lactic AcidLactobacillus
Mixed AcidEnterobacteriaceae
ButanediolKlebsiellaEnterobacter
Butyric AcidClostridia
Butanol-AcetoneClostridia
Propionic AcidCorynebacteria
Fermentation
Fermentation Pathways
Fermentation Summary
AnaerobicCytoplasmPartial OxidationSmall amounts of ATP generated via substrate level phosphorylationOrganic intermediaries as final electron acceptorsEnd products
Acid: Lactic Acid, Acetic Acid, Butryic Acid, AcetoneAlcohol: Ethanol, IsopropylGas : CO2, H2Contaminants
Summary
Carbohydrate Fermentation Tests
Phosphorylation
Substrate LevelDirect transfer of phosphateGlycolysis
Oxidative PhosphorylationElectron transferChemiosmosis
PhotophosphorylationLight energy to chemical energy
Substrate Level Phosphorylation
Aerobic Respiration
Mitochondria of Eukaryotes
Plasma [cell] membrane
Acetyl CoA Formation
Acetyl CoA Final Structure
Krebs Cycle
Oxidation in Krebs Cycle
Dehydrogenation
Use of hydrogen in oxidative reactions
Removal of electron from hydrogenCarried on vitamin B derivatives
Energy released is trapped in chemical bonds
Redox Reactions
Oxidation
Reduction
Catabolism + Anabolism
Eukaryotic ETC
Prokaryotic ETC
Vit B based FlavoproteinsIron based CytochromesCoEnzyme Q
ETC Steps
Electrons from NADH or FADH2 to flavoproteinsH+ pumped into periplasmElectrons transported
To Iron-Sulfur proteins from NADHTo CoQ from FADH2
CytochromesFinal Electron Acceptor
O2 if AerobicOther if Anaerobic
Proton Pump
ETC: NAD
ETC: Cytochromes
Cytochrome Oxidase
Oxidase Test
ATP Synthetase
Anaerobic Respiration
Use of another compound than O2 as final electron acceptor in the ETCExamples
Nitrate ion NO3-[Pseudomonas, E coli, Bacillus]
NO2-N2ON2
Sulfate ion SO4= to H2S
MethanogensCarbonate ion CO3= to CH4
Methanogens
Nitrogen Reduction Test
Nitrate Reduction+ with Zinc Nitrate Reduction
Neg with zincNitrate Reduction +
Other Catabolic Processes
ProteinDeaminationDecarboxylationDehydrogenation
LipidGlycerolFA
Beta oxidationAcetyl CoA
Biosynthesis
PolysaccharideKeto acidsAAGlycerol from FA
LipidGlycerol + FA
AAKeto acids + NH2
NucleotidesNitrogen bases from Keto acids + NH25 C sugars from alternate CH20 Metabolism
FunctionsPolysaccharide
Cell wall componentsLipid
Cell wallPlasma membranes
AA/ProteinCell wall / membrane componentsEnzymesToxins
NucleotideDNARNAATPNADNADP
Protein Synthesis and Enzyme Regulation
MetabolismSummary
Questions?