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 . The enzymes from yeast and rat also catalyse the methylation of 3-demethylubiquinol-6 and 3-demethylubiquinol-9, respectively (this activity is classified as EC 2.1.1.64, 3-demethylubiquinol 3-O-methyltransferase).
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).
the enzyme catalyzes two methylation steps in the biosynthesis of ubiquinone-6, 1. the methylation of 3,4-dihydroxy-5-hexaprenylbenzoate and 2. the methylation of 3-demethylubiquinol-6 (this reaction is classified as EC 2.1.1.64)
the enzyme catalyzes two methylation steps in the biosynthesis of ubiquinone-8, 1. the methylation of 3,4-dihydroxy-5-octaprenylbenzoate and 2. the methylation of 3-demethylubiquinol-8 (this reaction is classified as EC 2.1.1.64)
the enzyme catalyzes two methylation steps in the biosynthesis of ubiquinone-10, 1. the methylation of 5-all-trans-decaprenyl-3,4-dihydroxybenzoate and 2. the methylation of 3-demethylubiquinol-10 (this reaction is classified as EC 2.1.1.64)
wide substrate specificity. The enzyme methylates both eukaryotic substrates demethylubiquinol-3 (this activity is classified as EC 2.1.1.64) and 3,4-dihydroxy-5-farnesylbenzoic acid and the distinct prokaryotic substrate 3-((2E,6E)-farnesyl)benzene-1,2-diol
3,4-dihydroxy-5-all-trans-hexaprenylbenzoate is an intermediate in biosynthesis of ubiquinone-6 in Saccharomyces cerevisiae (that is methylated by the yeast enzyme CoQ3 to 4-hydroxy-3-methoxy-5-hexaprenylbenzoate). When expressed in multicopy, the human construct rescues the growth of a yeast coq3 null mutant on a nonfermentable carbon source and restores coenzyme Q biosynthesis, although at lower levels than that of wild type yeast
the enzyme catalyzes two methylation steps in the biosynthesis of ubiquinone-6, 1. the methylation of 3,4-dihydroxy-5-hexaprenylbenzoate and 2. the methylation of 3-demethylubiquinol-6 (this reaction is classified as EC 2.1.1.64)
the enzyme catalyzes two methylation steps in the biosynthesis of ubiquinone-8, 1. the methylation of 3,4-dihydroxy-5-octaprenylbenzoate and 2. the methylation of 3-demethylubiquinol-8 (this reaction is classified as EC 2.1.1.64)
the enzyme catalyzes two methylation steps in the biosynthesis of ubiquinone-10, 1. the methylation of 5-all-trans-decaprenyl-3,4-dihydroxybenzoate and 2. the methylation of 3-demethylubiquinol-10 (this reaction is classified as EC 2.1.1.64)
when expressed in multicopy, the human construct rescues the growth of a yeast coq3 null mutant on a nonfermentable carbon source and restores coenzyme Q biosynthesis, although at lower levels than that of wild type yeast
the levels of SAM-dependent methyltransferases Coq3 and Coq5 are decreased in the myocardial infarction groups. In addition, short-chain (C3) and medium-chain (C4-C12) acylcarnitine levels gradually decrease, whereas long-chain acylcarnitine (C14-18) levels increase in myocardial infarction
Cloning and functional expression of AtCOQ3, the Arabidopsis homologue of the yeast COQ3 gene, encoding a methyltransferase from the plant mitochondria involved in ubiquinone biosynthesis
Cloning of a rat cDNA encoding dihydroxypolyprenylbenzoate methyltransferase by functional complementation of a Saccharomyces cerevisiae mutant deficient in ubiquinone biosynthesis
Lee, P.T.; Strahan, J.; Shepherd, J.N., Clarke, C.F.: Coq3 and Coq4 define a polypeptide complex in yeast mitochondria for the biosynthesis of coenzyme Q
Restoring de novo coenzyme Q biosynthesis in Caenorhabditis elegans coq-3 mutants yields profound rescue compared to exogenous coenzyme Q supplementation