The enzymatic synthesis of fatty acid methyl esters by carboxyl group alkylation.

The reaction was studied by incubation of fatty acid with S-adenosyhnethionine-methylJ4C and isolation of the labeled ester. This was characterized by thin layer and gas-liquid chromatography and by isolation of labeled methanol from alkaline hydrolysates of the ester. Of several substrates tested only S-adenosylmethionine was an effective methyl donor (K,,, = 2.5 X 10F5 M) and oleic acid was the most effective fatty acid acceptor (Km = 1.3 x 10d3 M). Some methyl ester was formed when phospholipids were added to the incubation mixture, presumably because lipase action liberated fatty acids which could serve as substrates. The optimum pH for the reaction lay between 8 and 9. Some inhibition of the reaction was observed with calcium ion, while S-adenosylhomocysteine was a potent inhibitor.