PROPEPTIN, A NEW INHIBITOR OF PROLYL ENDOPEPTIDASE PRODUCED BY MICROBISPORA .1. FERMENTATION, ISOLATION AND BIOLOGICAL PROPERTIES

Propeptin, an inhibitor of the prolyl endopeptidase isolated from the mycelium of Microbispora sp. SNA-115, is an atypical cyclic peptide an tibiotic. It was purified by column chromatographies on silica gel and Sephadex LH-20 and high performance liquid chromatography using an OD S column. Propeptin has the molecular formula of C113H142N26O27 and co nsists of nineteen amino acids. Propeptin inhibited prolyl endopeptida se of the genus Flavobacterium competitively when Z-Gly-Pro-pNA was us ed as a substrate. The inhibitor constant (Ki) was 0.70 mu M.