Cholest-5-ene-3beta,7alpha-diol 3beta-dehydrogenase
Class of enzymes
From Wikipedia, the free encyclopedia
In enzymology, a cholest-5-ene-3β,7α-diol 3β-dehydrogenase (EC 1.1.1.181) is an enzyme that catalyzes several chemical reactions of steroids.[1]
| cholest-5-ene-3β,7α-diol 3β-dehydrogenase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC no. | 1.1.1.181 | ||||||||
| CAS no. | 56626-16-5 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / QuickGO | ||||||||
| |||||||||
The primary reaction is to convert 7α-hydroxycholesterol to 7α-hydroxycholest-4-en-3-one:[2]
The two substrates are 7α-hydroxycholesterol and oxidised nicotinamide adenine dinucleotide (NAD+). The products are 7α-hydroxycholest-4-en-3-one, reduced NADH, and a proton.[2]
The systematic name of this enzyme class is cholest-5-ene-3β,7α-diol:NAD+ 3-oxidoreductase. This enzyme is also called 3β-hydroxy-Δ5-C27-steroid oxidoreductase. The human version of this enzyme is known as hydroxy-Δ-5-steroid dehydrogenase, 3 β- and steroid delta-isomerase 7 or HSD3B7 which is encoded by the HSD3B7 gene.[3][4]
Function
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. This enzyme is involved in the initial stages of the synthesis of bile acids from cholesterol and a member of the short-chain dehydrogenase/reductase superfamily. This enzyme is a membrane-associated endoplasmic reticulum protein which is active against 7-alpha hydroxylated sterol substrates.[5]
Clinical significance
Mutations in the HSD3B7 gene are associated with a congenital bile acid synthesis defect which leads to neonatal cholestasis, a form of progressive liver disease.[5]
