Study on Mechanism in Hydrolysis of Peptide by Carboxypeptidase Y

Abstract

In order to evaluate the effect of the alkyl substituent at the nitrogen atom in amino acids and π-π interactions involving phenylalanine, dipeptides bearing N-methylglycine, N-methylalanine, and para-substituted phenylalanine were synthesized. The hydrolysis of 11 kinds of dipeptides catalyzed by carboxypeptidase Y and carboxypeptidase A was studied. There was found a good linear relationship between Michaelis-Menten constant K_m and hydrophobic parameters evaluated by reversed-phase HPLC. Also observed was a good linear relationship between catalytic constant k_cat in the enzymatic hydrolysis of the dipeptides and π-π interactions of monosubstituted benzene evaluated by graphitic carbon-phase HPLC.