title: Evidence for an 4-ene-3-oxosteroid-5alpha-reductase and delta4-delta5-ketosteroid isomerase activity in extracts of Streptomyces hydrogenans.
abstract: A homogenate of cells of Streptomyces hydrogenans which have been cultivated in the presence of estradiol-17beta, was separated by gel filtration on Sephadex G-200. In the presence of NADH, a few distinct fractions converted about 10% of [3H]toesterone to 5alpha-dihydrotesterone (5alpha-DHT), 5alpha-androstanedione, 4-androstenedione, and dehydroepiandrosterone (DHEA). The metabolites were separated after two consecutive runs on silica gel and propanediol-1,2-impregnated cellulose plates by thin layer chromatography. Identification was achieved by comparison with known steroid samples, specific staining procedures and by crystallization to constant specific radioactivity. The 5alpha-reductase activity responsible for the formation of 5alpha-DHT and 5alpha-androstanedione in vitro required NADH as co-substrate and could only be found after induction of the cells with estradiol-17beta in vivo. Within the same chromatographic fractions, a delta4-delta5-ketosteroid isomerase activity can be detected which catalyzes the reverse reaction from the 4-androstene testosterone to the 5-anthrostene DHEA in vitro.
mesh_terms: D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000378:metabolism*; D003600:Cytosol / Q000201:enzymology; D004790:Enzyme Induction / Q000187:drug effects; D004958:Estradiol / Q000494:pharmacology; D007535:Isomerases / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism*; D013251:Steroid Isomerases / Q000378:metabolism*; D013302:Streptomyces / Q000187:drug effects / Q000201:enzymology*; D013739:Testosterone / Q000378:metabolism
chemical_list: D013739:Testosterone; D004958:Estradiol; D010088:Oxidoreductases; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase; D007535:Isomerases; D013251:Steroid Isomerases