Succesive rouds of the cycle eventually lead to the total degradation of even-chain fatty acids in acetyl-CoA, which can be completely oxidized to CO2 through the : even-chain fatty acids cannot be used for net synthesis of oxaloacetate, and therefore are not a substrate for .
When acetyl-CoA is abundant, liver and adipose tissue synthesize fatty acids. The syntheis pathway is quite similar to the reverse of -oxidation, but presents several imporatant differences:
Fatty acid metabolism - What is Life HOME
The entry of acetyl CoA into the citric acid cycle depends on the availability of oxaloacetic acid for the formation of citric acid. In starvation or uncontrolled diabetes situations, oxaloacetic acid is used to synthesize glucose and is then not available for use with acetyl CoA. Under these conditions, acetyl CoA is diverted from the citric acid cycle to the formation of acetoacetic and 3-hydroxybutanoic acids.
Biochemistry: Lipid Metabolism - KUMC
The sequence of reactions involved in the formation of lipids is known as Lipogenesis. Lipogenesis is not simply the reverse of the fatty acid spiral, but does start with acetyl CoA and does build up by the addition of two carbons units. The synthesis occurs in the cytoplasm in contrast to the degradation (oxidation) which occurs in the mitochondria. Many of the enzymes for the fatty acid synthesis are organized into a multienzyme complex called fatty acid synthetase.