3-beta-HSD is a bifunctional enzyme, that catalyzes the oxidative conversion of Delta(5)-ene-3-beta-hydroxy steroid, and the oxidative conversion of ketosteroids. The 3-beta-HSD enzymatic system plays a crucial role in the biosynthesis of all classes of hormonal steroids. Efficiently catalyzes the transformation of pregnenolone to progesterone, 17-alpha-hydroxypregnenolone to 17-alpha-hydroxyprogesterone, DHEA to 4-androstenedione, dihydrotestosterone to 5-alpha-androstane-3 beta,17 beta-diol, dehydroepiandrosterone to androstenedione and 5-alpha-androstan-3 beta,17 beta-diol to 5-alpha-dihydrotestosterone.
Placenta and skin. Predominantly expressed in mammary gland tissue.