EC - Microsomal epoxide hydrolase

  IntEnz view ENZYME view

IntEnz Enzyme Nomenclature


Accepted name:
microsomal epoxide hydrolase
Other names:
epoxide hydratase [ambiguous]
microsomal epoxide hydratase [ambiguous]
epoxide hydrase
microsomal epoxide hydrase
arene-oxide hydratase [ambiguous]
benzo[a]pyrene-4,5-oxide hydratase
benzo(a)pyrene-4,5-epoxide hydratase
aryl epoxide hydrase [ambiguous]
cis-epoxide hydrolase
microsomal oxirane/oxetane hydrolase
Systematic name:
cis-stilbene-oxide hydrolase



This is a key hepatic enzyme that catalyses the hydrolytic ring opening of oxiranes (epoxides) and oxetanes to give the corresponding diols. The enzyme is involved in the metabolism of numerous substrates including the stereoselective hydrolytic ring opening of 7-oxabicyclo[4.1.0]hepta-2,4-dienes (arene oxides) to the corresponding trans-dihydrodiols. The reaction proceeds via a triad mechanism and involves the formation of an hydroxyalkyl-enzyme intermediate. Five epoxide-hydrolase enzymes have been identified in vertebrates to date: EC (leukotriene-A4 hydrolase), EC (hepoxilin-epoxide hydrolase), EC (microsomal epoxide hydrolase), EC (soluble epoxide hydrolase) and EC (cholesterol-5,6-oxide hydrolase).

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UM-BBD , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0033961


  1. Jakoby, W.B. and Fjellstedt, T.A.
    In: Boyer, P.D. (Ed.) The Enzymes , 3rd ed. vol. 7 , Academic Press , New York , 1972 , 199-212
  2. Lu, A.Y.H., Ryan, D., Jerina, D.M., Daly, J.W. and Levin, W.
    Liver microsomal epoxide hydrase. Solubilization, purification, and characterization.
    J. Biol. Chem. 250 : 8283-8288 (1975). [PMID: 240858]
  3. Oesch, F.
    Purification and specificity of a human microsomal epoxide hydratase.
    Biochem. J. 139 : 77-88 (1974). [PMID: 4463951]
  4. Oesch, F. and Daly, J.
    Solubilization, purification, and properties of a hepatic epoxide hydrase.
    Biochim. Biophys. Acta 227 : 692-697 (1971). [PMID: 4998715]
  5. Bellucci, G., Chiappe, C. and Ingrosso, G.
    Kinetics and stereochemistry of the microsomal epoxide hydrolase-catalyzed hydrolysis of cis-stilbene oxides.
    Chirality 6 : 577-582 (1994). [PMID: 7986671]
  6. Morisseau, C. and Hammock, B.D.
    Epoxide hydrolases: mechanisms, inhibitor designs, and biological roles.
    Annu. Rev. Pharmacol. Toxicol. 45 : 311-333 (2005). [PMID: 15822179]
  7. Fretland, A.J. and Omiecinski, C.J.
    Epoxide hydrolases: biochemistry and molecular biology.
    Chem. Biol. Interact. 129 : 41-59 (2000). [PMID: 11154734]
  8. Oesch, F.
    Mammalian epoxide hydrases: inducible enzymes catalysing the inactivation of carcinogenic and cytotoxic metabolites derived from aromatic and olefinic compounds.
    Xenobiotica 3 : 305-340 (1973). [PMID: 4584115]
  9. Newman, J.W., Morisseau, C. and Hammock, B.D.
    Epoxide hydrolases: their roles and interactions with lipid metabolism.
    Prog. Lipid Res. 44 : 1-51 (2005). [PMID: 15748653]
  10. Toselli, F., Fredenwall, M., Svensson, P., Li, X. Q., Johansson, A., Weidolf, L., Hayes, M. A.
    Oxetane Substrates of Human Microsomal Epoxide Hydrolase.
    Drug Metab. Dispos. 45 : 966-973 (2017). [PMID: 28600384]

[EC created 2006 (EC created 1978, modified 1999, part incorporated 2006), modified 2017]