Cholest-5-ene-3beta,7alpha-diol 3beta-dehydrogenase explained

cholest-5-ene-3β,7α-diol 3β-dehydrogenase
Ec Number:	1.1.1.181
Cas Number:	56626-16-5
Go Code:	0047016

hydroxy-Δ-5-steroid dehydrogenase, 3β- and steroid Δ-isomerase 7
Hgncid:	18324
Symbol:	HSD3B7
Entrezgene:	80270
Omim:	607764
Refseq:	NM_025193
Uniprot:	Q9H2F3
Ecnumber:	1.1.1.181
Chromosome:	16
Arm:	p
Band:	11.2

In enzymology, a cholest-5-ene-3β,7α-diol 3β-dehydrogenase is an enzyme that catalyzes the chemical reaction^[1]

cholest-5-ene-3β,7α-diol + NAD⁺

\rightleftharpoons 7α-hydroxycholest-4-en-3-one + NADH + H⁺

Thus, the two substrates of this enzyme are cholest-5-ene-3β,7α-diol and NAD⁺, whereas its 3 products are 7α-hydroxycholest-4-en-3-one, NADH, and H⁺.

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.^{[2] [3]}

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 hydrosylated sterol substrates.

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.^[4]

See also

• 3-beta-HSD

Notes and References

1. Wikvall K . Purification and properties of a 3 β-hydroxy-delta 5-C27-steroid oxidoreductase from rabbit liver microsomes . J. Biol. Chem. . 256 . 7 . 3376–80 . April 1981 . 10.1016/S0021-9258(19)69618-3 . 6937465 . free .
2. Schwarz M, Wright AC, Davis DL, Nazer H, Björkhem I, Russell DW . The bile acid synthetic gene 3β-hydroxy-Δ(5)-C(27)-steroid oxidoreductase is mutated in progressive intrahepatic cholestasis . J. Clin. Invest. . 106 . 9 . 1175–84 . November 2000 . 11067870 . 301421 . 10.1172/JCI10902 .
3. Persson B, Kallberg Y, Bray JE, Bruford E, Dellaporta SL, Favia AD, Duarte RG, Jörnvall H, Kavanagh KL, Kedishvili N, Kisiela M, Maser E, Mindnich R, Orchard S, Penning TM, Thornton JM, Adamski J, Oppermann U . The SDR (short-chain dehydrogenase/reductase and related enzymes) nomenclature initiative . Chem. Biol. Interact. . 178 . 1–3 . 94–8 . March 2009 . 19027726 . 2896744 . 10.1016/j.cbi.2008.10.040 . 2009CBI...178...94P .
4. Web site: Entrez Gene: HSD3B7 .