Tsuneo Harada

Enzymatic Production of Aspartame

Aspartame (1.-aspartyl-1.-phenylalanine methyl ester, APM) is the methyl ester of the terminal dipeptide of gastrin, the hormone that is released from the antral mucosa during digcstion. I t i s about 200 times as sweet as sucrose, and has a pleasant sweetness without a bitter aftertaste. Recently, i t was approved in many countries as a food additive. and is receiving much attention as a low-calorie sweetener. Proteinases catalyze the hydrolysis of peptide bonds. This is an equilibrium reaction. and thus a peptide bond may be formed in a significant yield if one can choose the proper enzymc and conditions. W e thought that aspartame might be synthesized enzymatically. After screening many enzymes, we found that some metalloproteinases that hydrolyze an amine or hydrophobic amino acids can catalyze the following react ions: