| Entry |
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| Name |
polyprenyldihydroxybenzoate methyltransferase;
3,4-dihydroxy-5-hexaprenylbenzoate methyltransferase;
dihydroxyhexaprenylbenzoate methyltransferase;
COQ3 (gene name);
Coq3 O-methyltransferase;
DHHB O-methyltransferase
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| Class |
Transferases;
Transferring one-carbon groups;
Methyltransferases
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| Sysname |
S-adenosyl-L-methionine:3,4-dihydroxy-5-all-trans-polyprenylbenzoate 3-O-methyltransferase
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| Reaction(IUBMB) |
S-adenosyl-L-methionine + 3,4-dihydroxy-5-all-trans-polyprenylbenzoate = S-adenosyl-L-homocysteine + 3-methoxy-4-hydroxy-5-all-trans-polyprenylbenzoate [RN: R08771]
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| Reaction(KEGG) |
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| Substrate |
S-adenosyl-L-methionine [CPD: C00019];
3,4-dihydroxy-5-all-trans-polyprenylbenzoate [CPD: C17554]
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| Product |
S-adenosyl-L-homocysteine [CPD: C00021];
3-methoxy-4-hydroxy-5-all-trans-polyprenylbenzoate [CPD: C17559]
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| Comment |
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 [3]. The enzymes from yeast and rat also catalyse the methylation of 3-demethylubiquinol-6 and 3-demethylubiquinol-9, respectively [2] (this activity is classified as EC 2.1.1.64, 3-demethylubiquinol 3-O-methyltransferase).
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| History |
EC 2.1.1.114 created 1999
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| Pathway |
| ec00130 | Ubiquinone and other terpenoid-quinone biosynthesis |
| ec01110 | Biosynthesis of secondary metabolites |
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| Orthology |
| K00591 | polyprenyldihydroxybenzoate methyltransferase / 3-demethylubiquinol 3-O-methyltransferase |
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| Genes |
» show all
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| Reference |
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| Authors |
Clarke CF, Williams W, Teruya JH. |
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| Title |
Ubiquinone biosynthesis in Saccharomyces cerevisiae. Isolation and sequence of COQ3, the 3,4-dihydroxy-5-hexaprenylbenzoate methyltransferase gene. |
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| Journal |
J Biol Chem 266:16636-44 (1991) |
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| Sequence |
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| Reference |
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| Authors |
Poon WW, Barkovich RJ, Hsu AY, Frankel A, Lee PT, Shepherd JN, Myles DC, Clarke CF |
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| Title |
Yeast and rat Coq3 and Escherichia coli UbiG polypeptides catalyze both O-methyltransferase steps in coenzyme Q biosynthesis. |
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| Journal |
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| Sequence |
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| Reference |
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| Authors |
Jonassen T, Clarke CF |
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| Title |
Isolation and functional expression of human COQ3, a gene encoding a methyltransferase required for ubiquinone biosynthesis. |
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| Journal |
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| Sequence |
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| Reference |
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| Authors |
Xing L, Zhu Y, Fang P, Wang J, Zeng F, Li X, Teng M, Li X |
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| Title |
Crystallization and preliminary crystallographic studies of UbiG, an O-methyltransferase from Escherichia coli. |
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| Journal |
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| Other DBs |
| ExPASy - ENZYME nomenclature database: | 2.1.1.114 |
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