DIVISION BASED ON STRUCTURE AND FUNCTION OF LIPIDLIPID STRUCTURE INFORMATION

SIMPLE LIPIDTriglycerol Consist of trihydric alcohol glycerol

esterifeid The structure is described by

“stereospecific numbering” sn system as recomended by an IUPAC-IUB commision

Reaction between two primary hydroxyl groups are esterified with different fatty acids yields asymmetric and thus can display “optical activity”.

Diacylglycerol Contain two moles and one mole of fatty acid per mole of glycerol

Exist in various isomeric forms Components of oil and fat Second messangers in many cellular

proccess2-monoacyl-sn-glycerol Formed as intermediets or end-products

of the enzymatic hydrolisis of triacylglicerols

Major end product of the intestinal digestion of dietary fats in animal via the enzyme pancreatic lipase

These and other positional isomers are powerful surfactants.

DIVISION BASED ON STRUCTURE AND FUNCTION OF LIPIDSterol and Sterol Ester

Plant Sterol From a group of triterpenes with a tetracyclic cyclopenta [a] phenanthrene structure and aside chain at carbon 17

These more common plant sterols have a double bond in position 5, and a definitive feature – a one- or two-carbon substituent with variable stereochemistry in the side chain at C-24, which is preserved during subsequent metabolism.

Sterol in Yeast and Fungi

Yeasts and fungi, together with microalgae and protozoa, can contain an enormous range of different sterols.

Ergosterol ((22E)-ergosta-5,7,22-trien-3β-ol) is the main sterol in fungi and yeasts.

Ergosterol are synthesised in yeast by the enzymes (ARE 1 and ARE 2) related to ACAT-1 and ACAT-2 (function in animal)

DIVISION BASED ON STRUCTURE AND FUNCTION OF LIPIDBacterial Sterol Hopanoids take the place of sterols in

many species of bacteria Some bacteria take up cholesterol and

other sterols from host animals for use as membrane constituens

Sterol Esters Sterol esters are present in plant tissues, but as minor components relative to the free sterols other than in waxes.

Usually the sterol components of sterol esters are similar to the free sterols, although there may be relatively less of stigmasterol.

Presumed to serve as inert storage forms of sterol

They have been found in the form of soluble lipoprotein complexes

Sterol Glycosides Leaf and other tissue in plants contain a range of sterol glycosides and acyl sterol glycosides, and typical examples (glucosides of β-sitosterol)

The carbohydrate moiety can sometimes be quite complex with up to five hexose units linked in a linear fashion.

DIVISION BASED ON STRUCTURE AND FUNCTION OF LIPIDWax Substance similar in composition and

physicel properties to bees wax Use in many comercial product

Tocopherols Only synthesised by plants and other oxygenic, photosynthetic organisems

Essential components of the diet animals Collectively they are turned “vitamin E”

Free (unsaturified) fatty Acid Free or unesterified fatty acids are ubiquitous if minor components of all living tissues.

In animals, much of the dietary lipid is hydrolysed to free acids before it is absorbed and utilized for lipid synthesis.

Monomeric is very low solubilities in aqueous media

GLYCEROPHOSPHOLIPIDPhosphatidic Acid Phosphatidic acid or 1,2-diacyl-sn-

glycero-3-phosphate is not an abundant lipid constituent of any living organism to my knowledge, but it is extremely important as an intermediate in the biosynthesis of triacylglycerols and phospholipids.

Act as intermediate in the bisynthesis of triacylglycerol and phospholipid

Signaling molecule Often over-estimated in tissues

DIVISION BASED ON STRUCTURE AND FUNCTION OF LIPIDLysophosphatidic Lysophosphatidic acid or 1-acyl-sn-

glycerol-3-phosphate differs from phosphatidic acid in having only one mole of fatty acid per mole of lipid.

The most important source is the activity of a specific lysophospholipase D known as ‘autotaxin’ on lysophosphatidylcholine (200 μM in plasma) to yield lysophosphatidic acid in an albumin-bound form.

Differs from phosphatidic acid is one mole of fatty acid per mole of lipid

The simplest possible glycerophospholipid.

Phosphatidyglycerol Found in plants, bacteria and animal tissues

In photocyntetic membrane of leaf of higher plants

It found unique in that high proportion of trans-3-hexadecenoic acid.

Found in sn2 stateCardiolipin Cardiolipin is the trivial but universally

used name for a lipid that should be correctly termed 'diphosphatidylglycerol' or more precisely 1,3-bis(sn-3'-phosphatidyl)-sn-glycerol.

It is a unique phospholipid with in essence a dimeric structure, having four acyl groups and potentially carrying two negative charges.

Tetra molecular species, important in heart, mithocondria

DIVISION BASED ON STRUCTURE AND FUNCTION OF LIPIDLysobiphosphatidic Bis(monoacylglycero)phosphate ('BMP')

is now known to be a common if minor constituent of all animal tissues.

It was first termed ‘lysobisphosphatidic acid’, although it is only superficially related to phosphatidic acid per se and can in fact be considered a structural isomer of phosphatidylglycerol.

It is easyliy misidentifeid as phophatidic acid in many chromatographic system

Phosphatidicoline Phosphatidylcholine (once given the trivial name 'lecithin') is usually the most abundant phospholipid in animal and plants, often amounting to almost 50% of the total, and as such it is obviously the key building block of membrane bilayers.

Very high proportion of outer leaflet of plasma membrane

Lysophosphatidycoline Contains only one fatty acid moiety in each molecule, generally in position sn-1, is sometimes present as a minor component of tissues.

It is a powerful surfactant and is more soluble in water than most other lipids.

DIVISION BASED ON STRUCTURE AND FUNCTION OF LIPIDPhosphatidylethanolammine Phosphatidylethanolamine (once given

the trivial name 'cephalin') is usually the second most abundant phospholipid in animal and plant lipids and it is frequently the main lipid component of microbial membranes.

Amount to 20% of lives phospholipid and as much as 45% of those of brain.

Phosphatidylserine Phosphatidylserine or 1,2-diacyl-sn-glycero-3-phospho-L-serine is distributed widely among animals, plants and microorganisms.

Less than 10% t-phospholipid Greatest concentration in myelin, brain

tissues

Phosphatidylinositol Phosphatidylinositol is a common constituent of animal, plant and microbial lipids.

In animal tissues especially, it may be accompanied by small amounts of phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate (and other 'poly-phosphoinositides').

Containing the optically inactive form of inositol, myo-inositol

DIVISION BASED ON STRUCTURE AND FUNCTION OF LIPIDPhosphonolipids Phosphonolipids consist of 2-

aminoethylphosphonic acid (ciliatine) residues, i.e. with a phosphorus-carbon bond, attached to a lipid backbone, which can be either a ceramide or diacylglycerol.

First time, found in sea anemones.

Ether Lipids In addition to diacyl forms, the membrane phospholipids of many animal and microbial species contain high proportions of molecular species with ether and vinyl ether bonds in positionsn-1, and often the vinyl ether or plasmalogen form predominates.

High proportion is in membrane phospholipid of many animals and microbial species

Platelet-Activating Factor PAF is synthesised by a variety of cells, but especially those involved in host defence, such as platelets, endothelial cells, neutrophils, monocytes, and macrophages.

Have messanger function

1-alkyl-2,3-diacyl-sn-glycerol On hydrolysis with alkali, the ether bond of 1-alkyldiacyl-sn-glycerols is stable, and 1-alkylglycerols and free (unesterified) acids are the products.

DIVISION BASED ON STRUCTURE AND FUNCTION OF LIPID

GLYCOCEROLIPID In plants, especially the photosynthetic tissues, a substantial proportion of the lipids consists of 1,2-diacyl-sn-glycerols joined by a glycosidic linkage at position sn-3 to a carbohydrate moiety.

SPHINGOMYELIN AND GLYCOSPHINGOLIPIDSLong Chain Bases Long-chain bases (sphingoids or

sphingoid bases) are the characteristic or defining structural unit of the sphingolipids.

The bases are long-chain aliphatic amines, containing two or three hydroxyl groups, and often a distinctive trans-double bond in position 4.

To be more precise, they are 2-amino-1,3-dihydroxy-alkanes or alkenes with (2S,3R)-erythrostereochemistry, with various further structural modifications.

DIVISION BASED ON STRUCTURE AND FUNCTION OF LIPID Most abundant in animal is sphingosine

Ceramides Ceramides consist of a long-chain or sphingoide base linked to a fatty acid via an amide bond.

They are rarely found as such at greater than trace levels in tissues, less than 10% of the glucosylceramide content in plants for example, although they can exert important biological effects.

Intermediate of biosynthesis complex sphingolipids

Sphingomyelin Sphingomyelin (or ceramide phosphorylcholine) consists of a ceramide unit with a phosphorylcholine moiety attached to position 1.

It is thus the sphingolipid analogue of phophatidycholine.

Ubiquitous component of animal Ceramide phosphorylethanolamine

Ceramide phosphorylethanolamine, the sphingolipid analogue of phosphatidylethanolamine, is a component of the lipids of insects, some fresh water invertebrates and many species of bacteria (where it is often accompanied by ceramide phosphorylglycerol), but it is present at trace levels only in mammalian cells.

A phospholipid analogue is found in certain organism

DIVISION BASED ON STRUCTURE AND FUNCTION OF LIPIDNeutral Glycosylceramides The most widespread glycosphingolipids

are the monoglycosylceramides (or cerebrosides), and they consist of a basic ceramide unit linked by a glycosidic bond at carbon 1 of the long-chain base to glucose or galactose.

First found in brain lipid.Lactocylceramides Non-acidic di- and

oligoglycosphingolipids, i.e. with two or more carbohydrate moieties attached to a ceramide unit, are vital components of cellular membranes of most eukaryotic organisms and some bacteria.

Abundance relative to other lipid is usually low.

Sulfoglycoshingolipid Glycosphingolipid sulfates (sometimes termed "sulfatides" or "sulfoglycosphingolipids") are glycosphingolipids carrying a sulfate ester group attached to the carbohydrate moiety.

First identified in brain tissues.Gangliosides The name ganglioside was first applied

by the German scientist Ernst Klenk in 1942 to lipids newly isolated from ganglion cells of brain.

Containing a sialic acid residue

DIVISION BASED ON STRUCTURE AND FUNCTION OF LIPIDSphingosine-1-phosphate Sphingosine-1-phosphate, a zwitterionic

lysophospholipid, is an important cellular metabolite, derived from ceramide that is synthesized de novo or as part of the sphingomyelin cycle in animal cells.

Zwiterionic lysophospho lipid An important cellular metabolit Found in insect, yeast and plants.

FATTY ACIDSaturated Fatty Acid Straight- or normal-chain, saturated

components (even-numbered) make up 10-40% of the total fatty acids in most natural lipids.

The most abundant saturated fatty acids in animal and plant tissues are straight-chain compounds with 14, 16 and 18 carbon atoms, but all the possible odd- and even-numbered homologues with 2 to 36 carbon atoms have been found in nature in esterified form.

DIVISION BASED ON STRUCTURE AND FUNCTION OF LIPIDMonoenoic Fatty Acid Straight- or normal-chain (even-

numbered), monoenoic components, i.e. with one double bond, make up a high proportion of the total fatty acids in most natural lipids.

Normally the double bond is of the cis- or Z-configuration, although some fatty acids with trans- or E-double bonds are known.

In animal and plants tissues straight chain, C16/C18

Polyunsaturated Fatty Acid The lipids of all higher organisms contain appreciable quantities of polyunsaturated fatty acids ('PUFA') with methylene-interrupted double bonds, i.e. with two or more double bonds of the cis-configuration separated by a single methylene group.

The term ‘homo-allylic’ is occasionally used to describe this molecular feature.

Most abundant contain in organism In higher plants, DBE max is 3 Synthesisd not in animal tissues

Branched-Chain Fatty Acid Branched-chain fatty acids are common constituents of the lipids of bacteria and animals, although they are rarely found in the integral lipids of higher plants.

Normally, the fatty acyl chain is saturated and the branch is a methyl-group. However, unsaturated

DIVISION BASED ON STRUCTURE AND FUNCTION OF LIPIDbranched-chain fatty acids are found in marine animals, and branches other than methyl may be present in microbial lipids.

ELCOSANIDE The term eicosanoid is used to embrace biologically active lipid mediators (C20 fatty acids and their metabolites), including prostaglandins, thromboxanes, leukotrienes and other oxygenated derivatives, which exert their effects at very low concentrations.

DIVISION BASED ON STRUCTURE AND FUNCTION OF LIPIDFUNCTION OF LIPID

• Fats are important fuel reserve molecules.

• Fats are energy rich so they provide concentrated energy, especially for muscle activity including the heart and respiratory system (breathing). Humans store fat reserves in adipose tissue. Adipose cells have a remarkable ability to swell and shrink depending on the amount of fat reserves they contain.

• Phospholipids are the primary structural molecules of cell membranes.

• Fats insulate from cold and provide padding for internal organs.

• Many hormones (regulatory chemicals) are steroids.

• Fats in the diet carry essential fat soluble vitamins: A, D, E and K

• Fats in the diet have satiety value – they stay in stomach longer so we feel fuller longer.

• Fats provide protective coatings on the body surfaces to help prevent dehydration.

• Second messengers in many cellular processes

• Modulating vital biochemical mechanisms.