The incorporation of citrate carbon into fatty acids

Abstract

Long-chain fatty acids are synthesized from citrate in an undialyzed soluble enzyme system from pigeon liver at a rate comparable to that observed when acetate is used as a precursor. The first enzymic step for citrate incorporation is probably its breakdown to acetyl-CoA and oxaloacetate catalyzed by the citrate-cleavage enzyme. Experiments with variously labeled citrate show good incorporation of the acetyl portion of citrate into fatty acids, and a poor incorporation of the oxaloacetyl portion into fatty acids. The incorporation of the oxaloacetyl portion of citrate as well as the acetyl portion has been shown to be avidin sensitive. The enzymic sequence from the oxaloacetyl portion remains uncertain.