Hog kidney and intestine aminoacylase-catalyzed acylation of L-methionine in aqueous media

Synthesis of N-acyl-L-methionine derivatives was catalyzed by hog kidney and intestinal aminoacylase in aqueous media using various acyl donors with acyl-chain lengths ranging from 1 to 6. Various reaction conditions were tested by varying the pH of the buffer, the water-miscible organic solvent and Zn2+ concentrations. Using short chain fatty acids, N-acyl-L-methionine derivatives were efficiently synthesized by both enzymes with a yield of about 20-30%, depending on the acid used. The optimal yield was achieved after a 17-h incubation of the reaction mixture containing 0.02 M acyl sodium salt, 0.2 M L-methionine, 10 mu M ZnCl2 and 120 mU of aminoacylase in a 0.2M sodium phosphate buffer at pH 6.0 and 37 degrees C. The part potentially played by acylase in the in vivo acylation of amino acids, and by extension that of proteins in general, is discussed.