The Use of Synthetic Polyamino Acids for the Detection and Purification of Novel Proteolytic Enzymes

Abstract

AbstractPolyamino acids were used as substrates for the detection and purification of new exopeptidases from bacteria. The enzymes, which were obtained in pure form and were characterized, include: aminopeptidase P, clostridial aminopeptidase, dipeptidocarboxypeptidase and a nonspecific dipeptidase. The possible application for sequential hydrolysis by the combined action of the two aminopeptidases was demonstrated by accomplishing complete hydrolysis of a proline‐rich nonapeptide, bradykinin. The dipeptidocarboxypeptidase, which produces dipeptides from the carboxyl end, and the dipeptidase, which then hydrolyses the dipeptides formed, indicate an efficient mechanism by which polypeptides are hydrolyzed from the carboxyl end of the molecule. The unique nature of the peptide bond, in which proline is involved through its nitrogen, is pointed out and the possible role of proline as a residue that protects terminal regions of polypeptides against the hydrolytic action of exopeptidases is discussed.