Biosynthesis of nanaomycin: syntheses of nanaomycin E from nanaomycin A and of nanaomycin B from nanaomycin E in a cell-free system.

The enzyme reactions from NNM-A to NNM-E and from NNM-E to NNM-B were established in a cell-free system containing an extract from the nanaomycin producer Streptomyces rosa var. notoensis. The enzyme which catalyses the former epoxide-forming reaction (NNM-A leads to NNM-E) required NADH (or NADPH) and O2 suggesting that it is the monooxygenase-type; thus, NNM-A monooxygenase (4a,10a-epoxidizing) is proposed as its name. The other enzyme which catalyses the reductive epoxide-opening reaction (NNM-E leads to NNM-B) requires NADH or NADPH and is tentatively named NNM-B synthetase. Such a reductive epoxide-opening reaction is a novel enzyme reaction.