PURIFICATION AND CHARACTERIZATION OF CRYSTALLINE MICROBIAL ALKALINE PROTEINASE-INHIBITORS (MAPI), PRODUCED BY STREPTOMYCES-NIGRESCENS WT-27

The three microbial alkaline proteinase inhibitors (alpha, beta and gamma-MAPI) have been obtained as needle crystalline forms by a combination of various adsorption and ionexchange column chromatographies. The crystalline inhibitors showed the same inhibitory spectrum but different inhibitory potential. They strongly inhibited various microbial alkaline proteinases, such as fungal alkaline proteinases, and also inhibited a-chymotrypsin, papain, ficin, bromelain and cathepsin B. The three MAPI gave positive Rydon-Smith, Sakaguchi and 2,4-dinitrophenylhydrazine reactions but were negative to ninhydrin reaction. From the amino acid analysis, three MAPI contained arginine, phenylalanine and some aliphatic amino acids; aliphatic amino acid of alpha-MAPI was valine only, that of beta-MAPI was probably valine (small amount of leucine and isoleucine was detected) and that of gamma-MAPI was leucine plus isoleucine (trace amount of valine was also detected). © 1979 Taylor & Francis Group, LLC.