Phosphatidate synthesis by sn-glycerol-3-phosphate acyltransferase in pigeon liver particles.

The properties of acyl-CoA: sn-glycerol-3-phosphate acyltransferase (EC 2.3.1.15) from pigeon liver particles have been studied. The apparent Km for snglycerol 3-phosphate was 50 PM. Acyl-CoA inhibited the enzyme at concentrations exceeding 60 PM. This inhibition can be overcome by adding extra protein. The enzyme was inhibited by thiol-binding agents. Protection from thiol-binding agents is achieved by preincubation of the enzyme with acyl-CoA. The amount of the thiol group protected per mg enzyme protein was estimated by adding radioactive Nethylmaleimide in the presence of glycerol phosphate. No evidence was obtained for required sulfhydryl groups other than those protected by acyl-CoA. In the presence of bovine serum albumin, several different acyl-CoA derivatives were esterified to sn-glycerol3-phosphate at very similar rates.