L-leucine and its analogue: Specific inhibitors for S-benzyl-L-cysteine-p-nitroanilide-hydrolyzing enzyme in Escherichia coli B

An enzyme that catalyzes hydrolysis of S-benzyl-L-cysteine-p-nitroanilide was purified from E. coli B. The enzyme was a monomer with a molecular weight of 82,000. In addition to L-cysteinylglycine, the enzyme hydrolyzed various glycine-containing dipeptides most efficiently at pH 7.0. The enzyme required no metal ions for activity and was specifically inhibited by L-leucine and its analogue with free carboxyl group at the physiological concentrations.