Characterization of the Mutant of Streptomyces sp. SL-387 (KCTC 0102BP) Producing Aminopeptidase M Inhibitors = Aminopeptidase M 저해제를 생산하는 Streptomyces sp. SL-387 (KCTC 0102BP) 변이주의 특성

Abstract

Since the original productivity of new aminopeptidase M inhibitors MR-387A and B by Streptomyces sp. SL-387 (KCTC 0102BP) was not enough for further chemical and biological evaluation, mutation of parent strain by the treatment of N-methyl-N'-nitro-N-nitrosoguanidine was performed in order to obtain a clone with greater inhibitory activity. Mutant N-3 was selected due to a 6-fold greater productivity (40 μg/ml) than that of the wild type(6.7 μg/ml). This mutant was resistant to 3,4-dehydro-DL-proline, an antimetabolite of proline, with 25 μg/ml of minimum inhibitory concentration. Furthermore, the characteristic morphological change from spiral spore chain in wild type to straight in mutant was observed. An aminopeptidase M nhibitor different from MR-387A and B was isolated from the culture broth of the mutant. This inhibitor was composed of 2 proline, 1 valine, and an unknown amino acid which is presumably 3-amino-4-phenylbutanoic acid. IC50 value (89.1 \MUg/ml) of the purified inhibitor was lower than that of other inhibitors, which may be due to the absence of 2(S)-hydroxyl group within the structure of 3-amino-4-phenyl- butanoic acid.