摘要：Menaquinone 7 (MW : 649, C46H64O2), a natural electron acceptor for steroid ring A dehydrogenations, produced by Bacillus sp. SNU-299, was isolated as a rat prostate testosterone 5α-reductase inhibitor with an IC50 value of 4.0×10-5 M from the cultured broth. Phylloquinone was as active as the purified microbial metabolite with an IC50 value of 6.6×10-4 M. On the basis of this evidence, the inhibitory activities of electron carriers, menadione, phenazine methosulfate, and 2, 6-dichlorophenolindophenol, for rat prostate testosterone 5α-reductase were tested, and the IC50 values were 3.1×10-6 M, 4.9×10-8 M, 8.9×10-5 M, respectively. A product of the 5α-reductase enzyme reaction and an electron and proton carrier, NADP+, inhibited the 5α-reduction by rat prostate testerone 5α-reductase with an IC50 value of 9.2×10-5 M. However, the inhibition effect of a proton carrier, carbonylcyanide-m-chlorophenylhydrazone, for rat prostate testosterone 5α-reductase was substantially inactive.
关键词：electron carrier;testosterone 5α-reductase inhibitor;menaquinone 7;Bacillus;phenazine methosulfate;steroid ring A dehydrogenation
