TAG Synthesis

TAG Synthesis

TAGs are comprised of a glycerol backbone and fatty acids.

TAG Synthesis in the Intestine

TAG synthesis occurs in intestinal cells following lipid digestion, in preparation for secretion as chylomicrons.

FFAs are first bound to CoA in an energy dependent process. FA-CoAs can then be attached to the2-MAG backbone by acyltransferases.

TAG Synthesis in the Liver and Adipose Tissue

Glycerol must first be phosphorylated in order to form TAGs. This occurs in the liver and adipose tissue in one of two ways.

The liver and adipose tissue can convert glucose into glycerol 3-P through action of glycerol-P dehydrogenase on DHAP, in the glycolysis pathway.

The liver can also phosphorylate glycerol directly, hence once liberated in the blood (by hormone-sensitive lipase) it returns to the liver for processing.

Glycerol phosphate combines with fatty acyl CoA from fatty acid synthesis to yield a 1,2 diglyceride and finally a triglyceride.

TAG Fate

Little fat is stored in the liver, instread being combined with apoproteins and other lipids to form VLDLs that are released into the blood.

Adipose stores of TAG form the body's major source of stored energy. Stores are released following binding of hormones, especially epinephrine, transduction through the cAMP pathway, and activation of hormone-sensitive lipase.