In enzymology, a cholest-5-ene-3β,7α-diol 3β-dehydrogenase (EC 1.1.1.181) is an enzyme that catalyzes the chemical reaction
- cholest-5-ene-3β,7α-diol + NAD+
7α-hydroxycholest-4-en-3-one + NADH + H+
Thus, the two substrates of this enzyme are cholest-5-ene-3β,7α-diol and NAD+, whereas its 3 products are 7α-hydroxycholest-4-en-3-one, NADH, and H+.
The systematic name of this enzyme class is cholest-5-ene-3β,7α-diol:NAD+ 3-oxidoreductase. This enzyme is also called 3β-hydroxy-Δ5-C27-steroid oxidoreductase. The human version of this enzyme is known as hydroxy-Δ-5-steroid dehydrogenase, 3 β- and steroid delta-isomerase 7 or HSD3B7 which is encoded by the HSD3B7 gene.