3beta hydroxy 5alpha steroid dehydrogenase

In enzymology, a 3β-hydroxy-5α-steroid dehydrogenase (EC 1.1.1.278) is an enzyme that catalyzes the chemical reaction

Thus, the two substrates of this enzyme are 3β-hydroxy-5α-pregnane-20-one (allopregnanolone) and NADP⁺, whereas its 3 products are 5α-pregnan-3,20-dione, NADPH, and H⁺.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD⁺ or NADP⁺ as acceptor. The systematic name of this enzyme class is 3β-hydroxy-5α-steroid:NADP⁺ 3-oxidoreductase.