hydroxy-Δ-5-steroid dehydrogenase, 3β- and steroid Δ-isomerase 1
Identifiers
Symbol	HSD3B1
Alt. symbols	HSDB3, HSD3B
Entrez	3283
HUGO	5217
OMIM	109715
RefSeq	NM_000862
UniProt	P14060
Other data
EC number	1.1.1.145
Locus	Chr. 1 p13-p11

hydroxy-Δ-5-steroid dehydrogenase, 3β- and steroid Δ-isomerase 2
Identifiers
Symbol	HSD3B2
Entrez	3284
HUGO	5218
OMIM	613890
RefSeq	NM_000198
UniProt	P26439
Other data
EC number	1.1.1.145
Locus	Chr. 1 p13.1

3β-Hydroxysteroid dehydrogenase/Δ^5-4 isomerase (3β-HSD) (EC 1.1.1.145) is an enzyme that catalyzes the biosynthesis of progesterone from pregnenolone, 17α-hydroxyprogesterone from 17α-hydroxypregnenolone, and androstenedione from dehydroepiandrosterone (DHEA) in the adrenal gland. It is the only enzyme in the adrenal pathway of corticosteroid synthesis that is not a member of the family. In humans, there are two 3β-HSD isozymes encoded by the HSD3B1 and HSD3B2 genes.

3β-HSD is also known as delta Δ^5-4-isomerase, which catalyzes the oxidative conversion of Δ^5-3-β-hydroxysteroids to the Δ^4-3-keto configuration and is, therefore, essential for the biosynthesis of all classes of hormonal steroids, namely progesterone, glucocorticoids, mineralocorticoids, androgens, and estrogens.

The 3β-HSD complex is responsible for the conversion of:

3β-HSD belongs to the family of oxidoreductases, to be specific, those acting on the CH-OH group of donor with NAD⁺ or NADP⁺ as acceptor. This enzyme participates in C21-steroid hormone metabolism and androgen and estrogen metabolism.

...
Wikipedia