Isolation and Partial Characterization of a Carboxypeptidase from Barley

Abstract

A carboxypeptidase has been purified from germinated barley. The preparations are homogeneous in ultracentrifugal analysis. In disc electrophoresis traces of impurities can be detected at high concentration. The purified enzyme liberates carboxyl‐terminal amino acid residues from a wide range of carbobenzoxy (Z)‐dipeptides. Peptides containing proline are not attacked. It does not possess any endopeptidase, aminopeptidase, or dipeptidase activity. The enzyme has a pH optimum at pH 5.2, is inhibited by di‐isopropylphosphofluoridate and p ‐chloromercuribenzoate, and has a molecular weight of about 90,000.