[Enzyme induction in Streptomyces hydrogenans. V. Characterization of testosterone-17 beta-dehydrogenase and its induction by steroids].
Testosterone 17beta-dehydrogenase can be enriched from Streptomyces hydrogenans. The enzyme dehydrogenizes testosterone with Km=13muM and estradiol-17beta with Km=21muM to the corresponding 17-ketoderivatives. NAD forms NADH with Km=125muM. The enzyme is strongly inhibited by androstandione and 17alpha-methyltestosterone. The Ki for 17alpha-methyltestosterone is 18muM. The enzyme activity increases with increasing pH up to alkali-mediated denaturation at about pH 10. The optimum temperature is at 45 degrees C. If Streptomyces hydrogenans is cultivated in the absence of steroids, the specific activity of testosterone 17beta-dehydrogenase in the cytosol of the microorganisms amounts to 10 mU/mg protein, and increases up to 10-fold if the cells are cultivated in the presence of certain steroids. Testosterone, alpha-dihydrotestosterone, beta-dihydrotestosterone, estradiol-17beta, and 17alpha-methyltestosterone are very effective inducers. Thus, for the first time, the ability of estradiol-17beta to induce an enzyme synthesis in a microorganism is shown. The steroid-dependent induction is inhibited by testosterone acetate and rifamycin SV. Cyproterone, however, does not decrease the testosterone-dependent enzyme induction of testosterone 17beta-dehydrogenase.
D015113:Androstane-3,17-diol / Q000494:pharmacology; D003534:Cyproterone / Q000494:pharmacology; D013196:Dihydrotestosterone / Q000494:pharmacology; D004355:Drug Stability; D004790:Enzyme Induction / Q000187:drug effects; D004958:Estradiol / Q000494:pharmacology; D004960:Estradiol Dehydrogenases; D006863:Hydrogen-Ion Concentration; D006913:Hydroxysteroid Dehydrogenases / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D007700:Kinetics; D008777:Methyltestosterone / Q000494:pharmacology; D008970:Molecular Weight; D009243:NAD / Q000378:metabolism; D012294:Rifamycins / Q000494:pharmacology; D013302:Streptomyces / Q000201:enzymology*; D013696:Temperature; D013739:Testosterone; D013997:Time Factors
D012294:Rifamycins; D013196:Dihydrotestosterone; D009243:NAD; D015113:Androstane-3,17-diol; D013739:Testosterone; D004958:Estradiol; D003534:Cyproterone; D006913:Hydroxysteroid Dehydrogenases; D004960:Estradiol Dehydrogenases; D008777:Methyltestosterone
Enzyminduktion bei Streptomyces hydrogenans, V. Charakterisierung der Testosteron-17beta-Dehydrogenase und ihre Induktion durch Steroide