HSD3B1

The protein encoded by this gene is an enzyme that catalyzes the oxidative conversion of delta-5-3-beta-hydroxysteroid precursors into delta-4-ketosteroids, which leads to the production of all classes of steroid hormones. The encoded protein also catalyzes the interconversion of 3-beta-hydroxy- and 3-keto-5-alpha-androstane steroids. [provided by RefSeq, Jun 2016]

Full Name

Hydroxy-Delta-5-Steroid Dehydrogenase, 3 Beta- And Steroid Delta-Isomerase 1

Function

A bifunctional enzyme responsible for the oxidation and isomerization of 3beta-hydroxy-Delta5-steroid precursors to 3-oxo-Delta4-steroids, an essential step in steroid hormone biosynthesis. Specifically catalyzes the conversion of pregnenolone to progesterone, 17alpha-hydroxypregnenolone to 17alpha-hydroxyprogesterone, dehydroepiandrosterone (DHEA) to 4-androstenedione, and androstenediol to testosterone. Additionally, catalyzes the interconversion between 3beta-hydroxy and 3-oxo-5alpha-androstane steroids controlling the bioavalability of the active forms. Specifically converts dihydrotestosterone to its inactive form 5alpha-androstanediol, that does not bind androgen receptor/AR. Also converts androstanedione, a precursor of testosterone and estrone, to epiandrosterone (PubMed:1401999, PubMed:2139411).

Expected to use NAD+ as preferred electron donor for the 3beta-hydroxy-steroid dehydrogenase activity and NADPH for the 3-ketosteroid reductase activity (Probable).

Biological Process

Androgen biosynthetic process Source: UniProtKB
C21-steroid hormone metabolic process Source: GO_Central
Estrogen biosynthetic process Source: UniProtKB
Hippocampus development Source: GO_Central
Response to corticosterone Source: GO_Central
Steroid biosynthetic process Source: UniProtKB

Cellular Location

Mitochondrion membrane; Endoplasmic reticulum membrane

Topology

Helical: 288-308