Lipogenesis

List the metabolically significant plasma lipid and their normal range.

Fatty acids (Free fatty acids)

Normal range: 0.2-0.6 mmol/L (6-16 mg/dl)

composed of:

Saturated and unsaturated fatty acid

Cholesterol

Normal range: 3.8- 6.7 mmol/L or 150- 250 mg/dl

composed of:

Free carbohydrate and esterified carbohydrate or cholesterol ester

Triacylglycererols (TAG)

normal range: 0.9- 2.0 mmol/L

Phospholipids

Normal range: 1.8-5.8 mmol/L

composed of:

glycerophospholipids

phosphatidylcoline

phosphatidyletanolamine

phosphatidylserine

phosphatidylinositol

Sphingophospholipid

Sphingomyelin

Definition of lipogenesis

synthesis of FA from acetyl- coA during the well fed state

Site Lipogenesis

LKBLMA

• Cytosol of cell in the liver, kidney, brain, lung, mamary gland and adipose tissue

Material required for Lipogenesis

Acetyl Coa, NADPH, ATP, Mn2+, biotin, and HCO3 as a source of CO2

What is the end product of Lipogenesis?

Free Palmitate

what are the 2 step involved in lipgenesis?

A. Formation of Malonyl Coa:

Acetyl Coa derrived from carbohydrate oxidation in mitochondria is carboxylated to malonyl Coa by acetyl Coa carboxylase.

enzyme activation by citrate and inhibited by long chain acyl- coa.

B. Formation of fatty acid from malonyl Coa:

catalysed by FA synthase (FAS). NADPH is required for FAS comes from the HMP pathway and other reactions.

Sources of NADPH for lipogenesis

HMP pathway

malic enzyme reaction (malate to pyruvate)

extramitochondrial isocitrate dehydrogenase

Source of Acetyl Coa

Oxidative decarboxylation of pyruvate to acetyl-coa within mitochondria

citrate translocates into the cytoplasm, undergoes cleavage to acetyl-coa and oxaloacetate by ATP citrate lyase

Biomedical important of beta oxidation