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Escherichia coli K-12 substr. MG1655 Reaction: 2.1.1.64

Superclasses: Reactions Classified By Conversion Type Simple Reactions Chemical Reactions
Reactions Classified By Substrate Small-Molecule Reactions

EC Number: 2.1.1.64

Enzymes and Genes:
bifunctional 3-demethylubiquinone-8 3-O-methyltransferase and 2-octaprenyl-6-hydroxyphenol methylase Inferred from experiment : ubiG

In Pathway: ubiquinol-8 biosynthesis (prokaryotic)

Note that this reaction equation differs from the official Enzyme Commission reaction equations for this EC number.

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

Most BioCyc compounds have been protonated to a reference pH value of 7.3, and some reactions have been computationally balanced for hydrogen by adding free protons. Please see the PGDB Concepts Guide for more information.

Mass balance status: Balanced.

Enzyme Commission Primary Name: 3-demethylubiquinol 3-O-methyltransferase

Enzyme Commission Synonyms: 5-demethylubiquinone-9 methyltransferase, OMHMB-methyltransferase, 2-octaprenyl-3-methyl-5-hydroxy-6-methoxy-1,4-benzoquinone methyltransferase, S-adenosyl-L-methionine:2-octaprenyl-3-methyl-5-hydroxy-6-methoxy-1,4-benzoquinone-O-methyltransferase, COQ3 (gene name), Coq3 O-methyltransferase, ubiG (gene name, ambiguous)

Summary:
This is the ninth and final step in ubiquinone biosynthesis.

Enzyme Commission Summary:
This enzyme is involved in ubiquinone biosynthesis. Ubiquinones from different organisms have a different number of prenyl units (for example, ubiquinone-6 in Saccharomyces, ubiquinone-9 in rat and ubiquinone-10 in human), and thus the natural substrate for the enzymes from different organisms has a different number of prenyl units. However, the enzyme usually shows a low degree of specificity regarding the number of prenyl units. For example, the human COQ3 enzyme can restore biosynthesis of ubiquinone-6 in coq3 deletion mutants of yeast [Poon99].

The enzymes from yeast, Escherichia coli and rat also catalyse the methylation of 3,4-dihydroxy-5-all-trans-polyprenylbenzoate [Poon99] (this reaction is classified as EC 2.1.1.114).

Citations: [Houser77, Leppik76a, Jonassen00]

Gene-Reaction Schematic: ?

Relationship Links: BRENDA:EC:2.1.1.64 , ENZYME:EC:2.1.1.64 , IUBMB-ExplorEnz:EC:2.1.1.64


References

Houser77: Houser RM, Olson RE (1977). "5-demethylubiquinone-9-methyltransferase from rat liver mitochondria. Characterization, localization, and solubilization." J Biol Chem 252(12);4017-21. PMID: 863914

Jonassen00: Jonassen T, Clarke CF (2000). "Isolation and functional expression of human COQ3, a gene encoding a methyltransferase required for ubiquinone biosynthesis." J Biol Chem 275(17);12381-7. PMID: 10777520

Leppik76a: Leppik RA, Stroobant P, Shineberg B, Young IG, Gibson F (1976). "Membrane-associated reactions in ubiquinone biosynthesis. 2-Octaprenyl-3-methyl-5-hydroxy-6-methoxy-1,4-benzoquinone methyltransferase." Biochim Biophys Acta 1976;428(1);146-56. PMID: 769831

Poon99: Poon WW, Barkovich RJ, Hsu AY, Frankel A, Lee PT, Shepherd JN, Myles DC, Clarke CF (1999). "Yeast and rat Coq3 and Escherichia coli UbiG polypeptides catalyze both O-methyltransferase steps in coenzyme Q biosynthesis." J Biol Chem 274(31);21665-72. PMID: 10419476


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of EcoCyc: Nucleic Acids Research 41:D605-12 2013
Page generated by SRI International Pathway Tools version 18.5 on Sat Nov 22, 2014, biocyc13.