LIPID CHEMISTRY

• LIPIDS ARE ORGANIC COMPOUNDS FOUND IN PLANTS AND ANIMALS.

– INSOLUBLE IN WATER BUT SOLUBLE IN ORGANIC SOLVENTS, e.g. ETHER, BENZENE, CHLOROFORM, ACETONE

– ARE ESTERS OF FATTY ACIDS OR SUBSTANCES CAPABLE OF FORMING SUCH ESTERS.

– UTILIZATION BY THE LIVING ORGANISM

FUNCTIONS OF LIPIDS

• COMPONENT OF ALL CELLS AND CELL ORGANELLES MEMBRANE

• MAJOR STORAGE FROM OF CARBON AND ENERGY

• METABOLIC FUEL AND EMULSIFYING AGENTS

• PRECURSORS OF OTHER IMPORTANT COMPOUNDS (PROSTAGLANDINS)

• INSULATING MATERIALS AGAINST ATMOSPHERIC HEAT OR COLD

• PROTECT ORGANS AGAINST PHYSICAL SHOCK

• PROTECTIVE COATING OF LIPID, PREVENT EXCESSIVE LOSS OF WATER AND INFECTIONS.

• TRANSPORT OF FAT SOLUBLE VITAMINS AND OTHER FAT SOLUBLE MATERIALS ACROSS CELL MEMBRANE

• FURNISHES ENERY TO BIOLOGICAL SYSTEM (9.1 KCAL/G)

FATTY ACIDS

• MAJOR PHYSIOLOGICAL ROLES

– BUILDING BLOCKS OF PL. AND GLYCO LIPID OF CELL MEMBRANS

– FATTY ACID DERIVATIVES ACT AS

• HORMONES

• INTERCELLULAR MESSENGER

– FATTY ACIDS ARE FUEL MOL & STORED AS TRIACYLGLYCEROL

CLASSIFICATION OF
FATTY ACIDS

• CHAIN LENGTH DEPENDENT

– SHORT CHAIN FATTY ACID [2-4 C]

– MEDIUM CHAIN FATTY ACID [6-10]

– LONG CHAIN FATTYACID [12-26 C]

MOST OF FATY ACID IN BLOOD BELONG TO THIS CLASS

• ESSENTIAL AND NON ESSENTIAL FATTY ACID

– LINOLEIC ACID = W6 SERIES

– LINOLENIC ACID = W3 SERIES

• SATURATED AND UNSATURATED

– MONO-ENOIC

– DI-ENOIC

– PLYUNSATURATED FATTY ACID

NOMENCLATURE OF FATTY ACIDS

• NUMBERING OF FATTY ACIDS FROM–COOH END ( D NUMBERING)

• OMEGA (w) NUMBERING OF FATTY ACIDS

• GREEK LETTERING SYSTEM a, b, g

• POSITION OF DOUBLE BONDS IS SHOWN FROM w OR D

CLASSIFICATION OF LIPIDS

1. SIMPLE LIPIDS
2. COMPLEX LIPIDS
3. PRECURSORS LIPIDS
4. STEROIDS

SIMPLE LIPIDS:

ALCOHOL + FATTY ACID

a. FATTY ACID - GLYCEROL

b. WAXES - HIGH MOL WT ALCOHOL + FATTY ACID

2. COMPLEX LIPIDS: ALCOHOL+F.A+OTHER GROUPS

I. PHOSPHOLIPIDS

a. GLYCEROPHOSPHOLIPDS: (ALCOHOL IS GLYCEROL)

• PHOSPHATIDIC ACID

• PHOSPHATIDYL GLYCEROL

• PHOSPHATIDYL CHOLINE

• PHOSPHATIDYL ETHANOLAMINE

• PHOSPHATIDYL INOSITOL

• PHOSPHATIDYL SERINE OR THREONIN

• LYSOPHOSPHOLIPIDS

• PLASMALOGENS. (ETHER LINKAGE)

b. SPHINGO PHOSPHO LIPID - SPHINGOMYLIN

II. GANGLIOSIDE

CERAMIDE – GLc – Gal – N. Acetylgalactosamine +Gal+Neuraminic acid

GMI GANGLIOSIDE

III. LIPOPOLYSACCHARIDES

– LIPID + POLYSACCHARIDE

OCCURS IN CELL WALLS OF CERTAIN BACTERIA

IV. LIPOPROTEINS

– LIPID CORE COVERED BY PROTEIN

OCCURS IN PLASMA

3. PRECURSORS AND DERIVED LIPIDS

– FATTY ACIDS

– GLYCEROL

– STEROIDS

– ALCOHOLS

– FATTY ALDEHYDES

– KETONE BODIES

– HYDROCARBONS

– LIPID SOLUBLE VITAMINS. VIT A, D, E & K

– HORMONES OF STEROIDS IN NATURE

4. STEROID/STEROLS

– CHOLESTEROL

FUNCTIONS OF CHOELSTEROL

• CELL MEMBRANES

• BIL ACID

• VITAMINE D

• REGULATION OF GENE

• STERIOD HORMONES

FUNCTIONS OF PROSTAGLANDIN

• SMOOTH MUSCLES CONTRACTION (PGE2&PGF2a)

• LOWER BLOOD PRESSURE

• REGULATE MENSTRUATION AND FERTILITY

• INDUCE LABOUR (PGE2 & PGF2a)

• CONTROL INFLAMMATION

• RELIEVE ASTHMA AND NASAL CONGESTION (PGE2 & PGI2)

• INDUCE BLOOD CLOTTING TX A2

• PREVENT BLOOD CLOTTING (PGI2)

• PREVENT CONCEPTION

CEREBROSIDES

• KERASIN

– FATTY ACID IS LIGNOCERIC ACID

• CEREBRON

– FATTY ACID IS HYDROXYLIGNOCERIC ACID

• NERVON

– FATTY ACID IS UNSATURATED HOMOLOUG LIGNOCERIC ACID

• OXYNERVON

– FATTY ACID IS HYDROXY DERIVATIVES OF NERVONIC ACID