Tags: Enzyme.
3-β-HSD (or 3-β-hydroxysteroid dehydrogenase/Δ-5-4 isomerase) (EC 1.1.1.145) is an enzyme that catalyzes the synthesis of progesterone from pregnenolone 17-hydroxyprogesterone from 17-hydroxypregnenolone and androstenedione from dehydroepiandrosterone in the adrenal gland. It is the only enzyme in the adrenal pathway of corticosteroid synthesis that is not a member of the Cytochrome P450 family.