NOVEL 26-OXYGENATED PRODUCTS IN MICROBIAL-DEGRADATION OF ERGOSTEROL

In order to investigate the effect of the different stereochemistry of C-24 on the microbial C-26 oxidation of sterol side-chain the genetic ally modified Mycobacterium sp. BCS 396 strain was used to transform e rgosterol. Ergosterol was converted to 3-oxo-4,22-ergostadien-26-oic a cid methyl ester, 3-oxo-1,4,22-ergostatrien-26-oic acid methyl ester, and 3-oxo-1,4,22-ergostatrien-26-oic acid, the structures of which hav e been determined by IR, H-1 NMR, C-13 NMR, and mass spectroscopy. The X-ray structure of 3-oxo-4,22-ergostadien-26-oic acid methyl ester re vealed that oxidation at C-26 of the ergostane side-chain generates a chiral center with S-configuration at C-25 as a result of chiral induc tion of the C-24 center.