Studies of the formation and utilization of bound CoA in glyceride biosynthesis

Abstract

1. 1. The formation of protein-bound CoA by the utilization of palmityl-CoA or palmitic acid activation for triglyceride biosynthesis has been demonstrated. The bound coenzyme is also formed enzymatically in the presence of ATP, Mg 2+ and CoA. 2. 2. When bound CoA was assayed for the presence of CoA by the citratecleavage enzyme or phosphate acetyltransferase, no CoA was detected. However, the requirement of CoA in the activation of fatty acids can be replaced by bound CoA. Both 2-monopalmitin and l-α-glycerophosphate serve as acyl acceptors in this sytem. 3. 3. Bound CoA acts catalytically. The fatty acid transfer reaction occurs in the presence of palmitic acid and ATP or palmityl-adenylate. 4. 4. Bound CoA is stable to heat inactivation and partially stable to trichloroacetic acid precipitation. The activity of bound CoA is destroyed enzymatically. However, the addition of ATP prevents this loss of activity. 5. 5. The formation and utilization of bound CoA is not affected by the prior treatment with certain sulphydryl reagents. However, the presence of N-ethylmaleimide during the acyl transfer completely inhibits this reaction.