NADPH-dependent 3-keto-steroid reductase Hsd3b4 (Hsd3b4)

The 3-beta-HSD enzymatic system plays a crucial role in the biosynthesis of all classes of hormonal steroids. HSD IV can only catalyze the conversion of dihydrotestosterone to 5 alpha- androstanediol in the presence of the cofactor NADPH.

Does not function as a isomerase. .