IUBMB Enzyme Nomenclature


Accepted name: squalene monooxygenase

Reaction: squalene + [reduced NADPH—hemoprotein reductase] + O2 = (3S)-2,3-epoxy-2,3-dihydrosqualene + [oxidized NADPH—hemoprotein reductase] + H2O

For diagram of reaction click here.

Other name(s): squalene epoxidase; squalene-2,3-epoxide cyclase; squalene 2,3-oxidocyclase; squalene hydroxylase; squalene oxydocyclase; squalene-2,3-epoxidase

Systematic name: squalene,NADPH:oxygen oxidoreductase (2,3-epoxidizing)

Comments: A flavoprotein (FAD). This enzyme, together with EC lanosterol synthase, was formerly known as squalene oxidocyclase. The electron donor is EC, NADPH—hemoprotein reductase [5,7].

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number:


1. Corey, E.J., Russey, W.E. and Ortiz de Montellano, P.R. 2,3-Oxidosqualene, an intermediate in the biological synthesis of sterols from squalene. J. Am. Chem. Soc. 88 (1966) 4750-4751. [PMID: 5918046]

2. Tchen, T.T. and Bloch, K. On the conversion of squalene to lanosterol in vitro. J. Biol. Chem. 226 (1957) 921-930. [PMID: 13438881]

3. van Tamelen, E.E., Willett, J.D., Clayton, R.B. and Lord, K.E. Enzymic conversion of squalene 2,3-oxide to lanosterol and cholesterol. J. Am. Chem. Soc. 88 (1966) 4752-4754. [PMID: 5918048]

4. Yamamoto, S. and Bloch, K. Studies on squalene epoxidase of rat liver. J. Biol. Chem. 245 (1970) 1670-1674. [PMID: 5438357]

5. Ono, T. and Bloch, K. Solubilization and partial characterization of rat liver squalene epoxidase. J. Biol. Chem. 250 (1975) 1571-1579. [PMID: 234459]

6. Satoh, T., Horie, M., Watanabe, H., Tsuchiya, Y. and Kamei, T. Enzymatic properties of squalene epoxidase from Saccharomyces cerevisiae. Biol. Pharm. Bull. 16 (1993) 349-352. [PMID: 8358382]

7. Chugh, A., Ray, A. and Gupta, J.B. Squalene epoxidase as hypocholesterolemic drug target revisited. Prog. Lipid Res. 42 (2003) 37-50. [PMID: 12467639]

8. He, F., Zhu, Y., He, M. and Zhang, Y. Molecular cloning and characterization of the gene encoding squalene epoxidase in Panax notoginseng. DNA Seq 19 (2008) 270-273. [PMID: 17852349]

[EC created 1961 as EC, transferred 1965 to EC, part transferred 1972 to EC, transferred 2011 to EC]

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