A 17 beta-hydroxysteroid dehydrogenase of female rabbit liver cytosol. Purification and characterization of multiple forms of the enzyme.
Multiple forms of the soluble 17 beta-hydroxysteroid dehydrogenase of female rabbit liver were identified. NAD-dependent and NADP-dependent enzyme activities were separated by affinity chromatography on agarose-immobilized Procion Red HE3B, and three forms of the NADP-dependent enzyme activity were purified by chromatofocusing. These three enzyme forms are charge isomers and have no quaternary structure. The enzymes catalysed the C-17 oxidoreduction of oestrogens and androgens; with all enzyme forms the activity towards androgens was higher than that toward oestrogens. The enzymes also exhibited 3 alpha-hydroxysteroid dehydrogenase activity towards androgens of the 5 beta-androstane series. Comparison of the relative activities of the enzymes towards a number of oestrogen and androgen substrates revealed differences among the enzyme forms for both the oxidative and the reductive reactions. In particular, one enzyme form had a significantly lower Km for the 3 alpha-hydroxysteroid substrate and a higher 3 alpha-/17 beta-hydroxysteroid dehydrogenase activity ratio than the other two enzyme forms.
Antoun
G R
GR
Brglez
I
I
Williamson
D G
DG
D015067:17-Hydroxysteroid Dehydrogenases / Q000302:isolation & purification / Q000378:metabolism*; D000818:Animals; D002846:Chromatography, Affinity; D003600:Cytosol / Q000201:enzymology; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D009249:NADP / Q000494:pharmacology; D011817:Rabbits; D013379:Substrate Specificity
D009249:NADP; D015067:17-Hydroxysteroid Dehydrogenases; C032690:3-alpha-(17-beta)-hydroxysteroid dehydrogenase (NAD(+))