Chemistry of lipids fatty acids ppt BIOCHEMISTRY

CHEMISTRY OF LIPIDSFATTY ACIDS

Dr. Vijay Marakala, MBBS, MD.

Assistant professor BIOCHEMISTRY SIMS & RC

FATTY ACIDS

Fatty acids are carboxylic acids with hydrocarbon side chain

R COOHHydrocarbon chain Carboxylic group

FATTY ACIDS

Esterified • Esterified with various lipids• Common

Free • FFA• Blood

Occurrence

FATTY ACIDS - CLASSIFICATION

D/U Total no of carbon atoms

Even chain FA

Odd chain FA

D/U Length of hydrocarbon chain

Short chain FA

Medium chain FA

Long chain FA

Very long chain FA

D/U Nature of hydrocarbon chain

Saturated FA

Unsaturated FA

Branched chain FA

Hydroxy FA

EVEN CHAIN FA

Most of the fatty acids that occur in natural lipids are even carbons.

ODD CHAIN FATTY ACIDS

Propionic acid

• 3 Carbon

Valeric acid

• 5 Carbon

Seen in milk and microbial cell walls

SATURATED FATTY ACIDS

In which hydrocarbon side chain is saturated (no double bonds).

SATURATED FATTY ACIDS

In which hydrocarbon side chain is unsaturated. One or more double bonds are present.

Monounsaturated FA

• One double bond

Polyunsaturated FA

• 2 or more double bonds

Subclassified according to number of double bonds

UNSATURATED FATTY ACIDS

UNSATURATED FATTY ACIDS

UNSATURATED FATTY ACIDS

SATURATED & UNSATURATED FA

Numbering of carbon atoms in FA

CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-COOH16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1

αβω

Carboxyl endMethyl end

Palmitic acid

Nomenclature of Fatty Acids

Saturated fatty acids

Saturated FA have both trivial names and systematic names.

Usually saturated FA end as anoic acids.

Nomenclature of Fatty Acids

Unsaturated fatty acids

They have trivial names, systematic names, ω-end names and shorthand forms.

Usually Unsaturated FA end as enoic acids.

Unsaturated fatty acids

Representation of double bonds of FA 2 systems

1. C-System

2. ω-or n-System

Nomenclature of Fatty Acids

1. C-System

CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH=CH-(CH2)7 -COOH18 17 16 15 14 13 12 11 10 9 8 1

Oleic acid (C:18:1:∆9)

2. ω-or n-System

CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH=CH-(CH2)7 -COOH1 2 3 4 5 6 7 8 9 10 11 18

Oleic acid (C:18:1:ω-9)

ESSENTIAL FATTY ACIDS

They are not synthesized in the body.

So they must be obtained from diet.

They are also called as poly unsaturated fatty acids

(PUFA).

They are - Linoleic acid (LA),

- Linolenic acid (LNA) and

- Arachidonic acid (AA).

Functions of EFA

1.Synthesis of Ecosanoids

2.Maintenance of structural integrity of cells

3.Development of retina and brain

4.Antiatherogenic effect

Thromboxanes Leukotrienes Prostaglandins

EFA deficiency

Occurs if EFAs are excluded from diet for long period

The syndrome in humans characterized by

Horny eruptions on the posterior and lateral parts of limbs, on the back and buttocks.Dermatitis Poor wound healing

Phrynoderma