Probestin, a new inhibitor of aminopeptidase M, produced by Streptomyces azureus MH663-2F6. I. Taxonomy, production, isolation, physico-chemical properties and biological activities.

Abstract
Probestin has been isolated as part of a program designed to find microorganism-produced inhibitors of aminopeptidase M from Streptomyces azureus MH663-2F6. It was purified by use of column chromatography of Amberlite XAD-4, silica gel, YMC-gel, Toyopearl HW-40, YMC D-ODS-5 (HPLC) and then isolated as colorless powders. Probestin is competitive with the substrate, and the inhibition constant (Ki) of it was 1.9 .times. 10-8 M.