17-Hydroxysteroid dehydrogenases of Mycobacterium sp. VKM Ac-1815D mutant strain

Whole cells and crude extract of Mycobacterium sp. VKM Ac-1815D mutant strain Et1 were shown to carry out 17beta-reduction, 17beta-dehydrogenation and 1(2)-reduction of 3-keto-C(19)-steroids. Two 17-hydroxy steroid dehydrogenases (17-OH SDH) were partially purified from the strain by ammonium sulfate fractionation, ion-exchange chromatography on DEAE-sephacel and gel-filtration on Bio-Gel A. The enzymes differed in chromatographic properties and specific activities. One enzyme--17-OH SDH (2) (tetramer, M(r) approximately 210,000) was found to be responsible for bi-directional reduction-oxidation of steroids at C 17, whereas the other one--17-OH SDH (1) (monomer, M(r) approximately 68,000) specifically catalysed 17beta-dehydrogenation of 17-hydroxysteroids (testosterone and 1(2)-dehydro testosterone). The 17beta-reduction of 1-ene-17-ketosteroids was accompanied by 1(2)-reduction. A role of 1-ene-reductase as a steroid-binding protein associated with 17-OH SDH (2) in Mycobacterium sp. is discussed.