Phosphatidic acid synthesis in Escherichia coli

Abstract

The kinetic properties of acyl-coenzyme A (CoA): l-alpha-glycerol-phosphate trans-acylase (EC 2.3.1.15) from Escherichia coli were studied. At 10 C, a temperature at which the reaction was proportional to time and enzyme concentration, the enzyme had an apparent K(m) of 60 mum for l-alpha-glycerol-phosphate. The curve describing the velocity of the reaction as a function of palmitoyl-CoA concentration was sigmoid but the plot of v(-1) versus [S](-3) gave a straight line. A K(m) of about 11 mum was calculated for palmitoyl-CoA. Adenosine triphosphate specifically inhibited the reaction, being a noncompetitive inhibitor in respect to l-alpha-glycerol phosphate. Inhibition only occurred with high concentrations of palmitoyl-CoA, and maximal inhibition was 60%.