IUBMB Enzyme Nomenclature


Accepted name: 3-demethoxyubiquinol 3-hydroxylase

Reaction: 6-methoxy-3-methyl-2-(all-trans-polyprenyl)-1,4-benzoquinol + a reduced acceptor + O2 = 3-demethylubiquinol + acceptor + H2O

For diagram of reaction click here.

Glossary: 3-demethylubiquinol = 3-methoxy-6-methyl-5-(all trans-polyprenyl)benzene-1,2,4-triol

Other name(s): 6-methoxy-3-methyl-2-(all-trans-polyprenyl)-1,4-benzoquinol 5-hydroxylase; COQ7 (gene name); clk-1 (gene name); ubiF (gene name)

Systematic name: 6-methoxy-3-methyl-2-(all-trans-polyprenyl)-1,4-benzoquinol,acceptor:oxygen oxidoreductase (5-hydroxylating)

Comments: The enzyme catalyses the last hydroxylation reaction during the biosynthesis of ubiquinone.

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


1. Marbois, B.N. and Clarke, C.F. The COQ7 gene encodes a protein in Saccharomyces cerevisiae necessary for ubiquinone biosynthesis. J. Biol. Chem. 271 (1996) 2995-3004. [PMID: 8621692]

2. Vajo, Z., King, L.M., Jonassen, T., Wilkin, D.J., Ho, N., Munnich, A., Clarke, C.F. and Francomano, C.A. Conservation of the Caenorhabditis elegans timing gene clk-1 from yeast to human: a gene required for ubiquinone biosynthesis with potential implications for aging. Mamm Genome 10 (1999) 1000-1004. [PMID: 10501970]

3. Kwon, O., Kotsakis, A. and Meganathan, R. Ubiquinone (coenzyme Q) biosynthesis in Escherichia coli: identification of the ubiF gene. FEMS Microbiol. Lett. 186 (2000) 157-161. [PMID: 10802164]

4. Stenmark, P., Grunler, J., Mattsson, J., Sindelar, P.J., Nordlund, P. and Berthold, D.A. A new member of the family of di-iron carboxylate proteins. Coq7 (clk-1), a membrane-bound hydroxylase involved in ubiquinone biosynthesis. J. Biol. Chem. 276 (2001) 33297-33300. [PMID: 11435415]

5. Tran, U.C., Marbois, B., Gin, P., Gulmezian, M., Jonassen, T. and Clarke, C.F. Complementation of Saccharomyces cerevisiae coq7 mutants by mitochondrial targeting of the Escherichia coli UbiF polypeptide: two functions of yeast Coq7 polypeptide in coenzyme Q biosynthesis. J. Biol. Chem. 281 (2006) 16401-16409. [PMID: 16624818]

[EC created 2018]

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