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Estradiol 17 beta-dehydrogenase and 20 alpha-hydroxysteroid dehydrogenase from human placental cytosol: one enzyme with two activities? 1980

R C Strickler, and B Tobias

The soluble enzyme estradiol 17 beta-dehydrogenase (17 beta-ED) from human term placental cytosol is reported to be a stereospecific oxidoreductase for estrogen substrates. A published purification scheme (heat treatment and affinity chromatography) yielded a homogeneous protein which had the reported characteristics of pure 17 beta-ED and also had 20 alpha-hydroxysteroid dehydrogenase (20 alpha-HSD) activity. Spectrophotometric assay when the buffer contained albumin, 8 mg/ml, masked the 20 alpha-HSD activity observed in albumin-free conditions and may explain why this bifunctional activity has gone unrecognized. In human placenta, one enzyme may catalyze stereospecific oxidation/reduction of both estrogen and progesterone.

UI MeSH Term Description Entries
D010920 Placenta A highly vascularized mammalian fetal-maternal organ and major site of transport of oxygen, nutrients, and fetal waste products. It includes a fetal portion (CHORIONIC VILLI) derived from TROPHOBLASTS and a maternal portion (DECIDUA) derived from the uterine ENDOMETRIUM. The placenta produces an array of steroid, protein and peptide hormones (PLACENTAL HORMONES). Placentoma, Normal,Placentome,Placentas,Placentomes
D003600 Cytosol Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components. Cytosols
D004960 Estradiol Dehydrogenases Enzymes that catalyze the oxidation of estradiol at the 17-hydroxyl group in the presence of NAD+ or NADP+ to yield estrone and NADH or NADPH. The 17-hydroxyl group can be in the alpha- or beta-configuration. EC 1.1.1.62 17 beta-Estradiol Dehydrogenase,Estradiol 17 alpha-Dehydrogenase,Estradiol 17 beta-Dehydrogenase,Estradiol Dehydrogenase,17 alpha-Dehydrogenase, Estradiol,17 beta Estradiol Dehydrogenase,17 beta-Dehydrogenase, Estradiol,Dehydrogenase, 17 beta-Estradiol,Dehydrogenase, Estradiol,Dehydrogenases, Estradiol,Estradiol 17 alpha Dehydrogenase,Estradiol 17 beta Dehydrogenase
D005260 Female Females
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D013056 Spectrophotometry, Ultraviolet Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed) Ultraviolet Spectrophotometry
D015067 17-Hydroxysteroid Dehydrogenases A class of enzymes that catalyzes the oxidation of 17-hydroxysteroids to 17-ketosteroids. EC 1.1.-. 17 beta-Hydroxysteroid Dehydrogenases,Testosterone Dehydrogenases,17-Ketosteroid Reductases,17 Hydroxysteroid Dehydrogenases,17 Ketosteroid Reductases,17 beta Hydroxysteroid Dehydrogenases,Dehydrogenases, 17 beta-Hydroxysteroid,Dehydrogenases, 17-Hydroxysteroid,Dehydrogenases, Testosterone,Reductases, 17-Ketosteroid
D015089 20-Hydroxysteroid Dehydrogenases A group of enzymes that catalyze the reversible reduction-oxidation reaction of 20-hydroxysteroids, such as from a 20-ketosteroid to a 20-alpha-hydroxysteroid (EC 1.1.1.149) or to a 20-beta-hydroxysteroid (EC 1.1.1.53). 20 Hydroxysteroid Dehydrogenases,Dehydrogenases, 20 Hydroxysteroid,Dehydrogenases, 20-Hydroxysteroid,Hydroxysteroid Dehydrogenases, 20

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