Reaction: (1) 5,6α-epoxy-5α-cholestan-3β-ol + H2O = 5α-cholestane-3β,5α,6β-triol
(2) 5,6β-epoxy-5β-cholestan-3β-ol + H2O = 5α-cholestane-3β,5α,6β-triol
For diagram click here.
Glossary: cholesterol = cholest-5-en-3β-ol
Other name(s): cholesterol-epoxide hydrolase; ChEH
Systematic name: 5,6α-epoxy-5α-cholestan-3β-ol hydrolase
Comments: The enzyme appears to work equally well with either epoxide as substrate . The product is a competitive inhibitor of the reaction. In vertebrates, five epoxide-hydrolase enzymes have been identified to date: EC 220.127.116.11 (leukotriene-A4 hydrolase), EC 18.104.22.168 (hepoxilin-epoxide hydrolase), EC 22.214.171.124 (microsomal epoxide hydrolase), EC 126.96.36.199 (soluble epoxide hydrolase) and EC 188.8.131.52 (cholesterol 5,6-oxide hydrolase) .
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:
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2. Oesch, F., Timms, C.W., Walker, C.H., Guenthner, T.M., Sparrow, A., Watabe, T. and Wolf, C.R. Existence of multiple forms of microsomal epoxide hydrolases with radically different substrate specificities. Carcinogenesis 5 (1984) 7-9. [PMID: 6690087]
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