The Primary Structure of Pepstatin-Insensitive Carboxyl Proteinase Produced by Pseudomonas sp. No. 101

Abstract

A unique carboxyl proteinase [EC 3.4.23.33] from Pseudomonas sp. No. 101 is the first example of a prokaryotic enzyme which is insensitive to the classical inhibitor, pepstatin. The primary structure of the proteinase was determined by conventional methods. Pseudomonas carboxyl proteinase consists of 370 amino acid residues with one disulfide bond. This enzyme has no homologous sequence with any other known carboxyl proteinase, including carboxyl proteinase B from Scytalidium lignicolum, which is a pepstatin-insensitive carboxyl proteinase. In addition, Pseudomonas carboxyl proteinase lacks the Asp*-Thr-Gly, Glu*-Thr-Gly, and Asp*-Thr-Ser-Gly (*indicates the catalytic residue) sequences which are known as the motif sequences around a pair of catalytic residues in carboxyl proteinases reported so far. The results strongly indicate that Pseudomonas carboxyl proteinase is a new type of carboxyl proteinase.