Hydrolases;
Acting on ether bonds;
Ether hydrolases

5,6alpha-epoxy-5alpha-cholestan-3beta-ol hydrolase

(1) 5,6alpha-epoxy-5alpha-cholestan-3beta-ol + H2O = 5alpha-cholestane-3beta,5alpha,6beta-triol [RN:R07597];
(2) 5,6beta-epoxy-5beta-cholestan-3beta-ol + H2O = 5alpha-cholestane-3beta,5alpha,6beta-triol [RN:R04792]

R04792 R07597

5,6alpha-epoxy-5alpha-cholestan-3beta-ol [CPD:C15992];
H2O [CPD:C00001];
5,6beta-epoxy-5beta-cholestan-3beta-ol [CPD:C05418]

The enzyme appears to work equally well with either epoxide as substrate [3]. The product is a competitive inhibitor of the reaction. In vertebrates, five epoxide-hydrolase enzymes have been identified to date: EC 3.3.2.6 (leukotriene-A4 hydrolase), EC 3.3.2.7 (hepoxilin-epoxide hydrolase), EC 3.3.2.9 (microsomal epoxide hydrolase), EC 3.3.2.10 (soluble epoxide hydrolase) and EC 3.3.2.11 (cholesterol 5,6-oxide hydrolase) [3].

EC 3.3.2.11 created 2006

1  [PMID:6401984]

Levin W, Michaud DP, Thomas PE, Jerina DM.

Distinct rat hepatic microsomal epoxide hydrolases catalyze the hydration of cholesterol 5,6 alpha-oxide and certain xenobiotic alkene and arene oxides.

Arch Biochem Biophys 220:485-94 (1983)
DOI:10.1016/0003-9861(83)90439-3

2  [PMID:6690087]

Oesch F, Timms CW, Walker CH, Guenthner TM, Sparrow A, Watabe T, Wolf CR.

Existence of multiple forms of microsomal epoxide hydrolases with radically different substrate specificities.

Carcinogenesis 5:7-9 (1984)
DOI:10.1093/carcin/5.1.7

3  [PMID:3941086]

Sevanian A, McLeod LL.

Catalytic properties and inhibition of hepatic cholesterol-epoxide hydrolase.

J Biol Chem 261:54-9 (1986)

4  [PMID:11154734]

Fretland AJ, Omiecinski CJ.

Epoxide hydrolases: biochemistry and molecular biology.

Chem Biol Interact 129:41-59 (2000)
DOI:10.1016/S0009-2797(00)00197-6

5  [PMID:15748653]

Newman JW, Morisseau C, Hammock BD.

Epoxide hydrolases: their roles and interactions with lipid metabolism.

Prog Lipid Res 44:1-51 (2005)
DOI:10.1016/j.plipres.2004.10.001