The enzymatic synthesis of triglycerides.

Although there is good evidence that the formation of new ester bonds may be catalyzed by lipolytic enzymes (1) it appears unlikely that such a mechanism could account for any very substantial net synthesis of triglyceride. The first evidence for a pathway of biosynthesis clearly different from the reversal of hydrolysis was provided by Tietz and Shapiro (2) who showed that the incorporation of labeled fatty acid into neutral fat in homogenates of liver required adenosine triphosphate. Identification of phosphatidic acids and ~-a! ,&diglycerides as essential intermediates in the biosynthesis of glycerophosphatides led to the hypothesis that these compounds may also be precursors of triglycerides. In confirmation of this hypothesis, we have found an enzyme in chicken liver Fhich catalyzes the net synthesis of triglyceride according to the following equation: