Action of carboxypeptidase W on oligopeptides containing carboxy- terminally amidated peptides

Article abstract of DOI:10.1016/S0031-9422(97)00074-5

Carboxypeptidase W sequentially liberated amino acids from the carboxy- terminus of angiotensin 1, bradykinin, delta sleep-inducing peptide and neurotensin, indicating that the sequential hydrolysis of peptides was limited by the occurrence of intermediates with the structure -Gly-X (X = L- amino acid), -Pro-X, -X-Gly and -X-Pro. The enzyme had carboxyamidase and/or amidase activities for the carboxy-terminally amidated peptides and then carboxypeptidase activity. Carboxyamidase activity of the enzyme for the carboxy-terminally amidated peptides tested was much lower than carboxypeptidase activity for Z-Glu-Tyr (Z = benzyloxycarbonyl). The enzyme essentially acted as a carboxyamidase for the long carboxy-terminally amidated peptides; an amidase became dominant for the substrates in the presence of a hydrophobic amino acid in the penultimate (P₁) or P₂ positions, especially the P₁ position, corresponding with the S₁ and S₂ sites of the enzyme.