Tags: Enzyme.
In enzymology a 3-β(or 20-α)-hydroxysteroid dehydrogenase (EC 1.1.1.210) is an enzyme that catalyzes the chemical reaction5α-androstan-3β17β-diol + NADP+ 17β-hydroxy-5α-androstan-3-one + NADPH + H+This enzyme possesses the combined activities of the 3-β-hydroxysteroid dehydrogenase/Δ-5-4 isomerase and 20-α-hydroxysteroid dehydrogenase enzymes.