IUBMB Enzyme Nomenclature

EC 2.1.1.83

Accepted name: 3,7-dimethylquercetin 4'-O-methyltransferase

Reaction: S-adenosyl-L-methionine + 5,3',4'-trihydroxy-3,7-dimethoxyflavone = S-adenosyl-L-homocysteine + 5,3'-dihydroxy-3,7,4'-trimethoxyflavone

For diagram click here.

Other name(s): flavonol 4'-O-methyltransferase; flavonol 4'-methyltransferase; 4'-OMT; S-adenosyl-L-methionine:3',4',5-trihydroxy-3,7-dimethoxyflavone 4'-O-methyltransferase; 3,7-dimethylquercitin 4'-O-methyltransferase [mis-spelt]

Systematic name: S-adenosyl-L-methionine:5,3',4'-trihydroxy-3,7-dimethoxyflavone 4'-O-methyltransferase

Comments: 3,7-Dimethylquercetagetin can also act as acceptor. Involved with EC 2.1.1.76 quercetin 3-O-methyltransferase and EC 2.1.1.82 3-methylquercetin 7-O-methyltransferase in the methylation of quercetin to 3,7,4'-trimethylquercetin in Chrysosplenium americanum. Does not act on flavones, dihydroflavonols, or their glucosides.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 96477-60-0

References:

1. De Luca, V. and Ibrahim, R.K. Enzymatic synthesis of polymethylated flavonols in Chrysosplenium americanum. I. Partial purification and some properties of S-adenosyl-L-methionine:flavonol 3-, 6-, 7-, and 4'-O-methyltransferases. Arch. Biochem. Biophys. 238 (1985) 596-605. [PMID: 3994393]

2. De Luca, V. and Ibrahim, R.K. Enzymatic synthesis of polymethylated flavonols in Chrysosplenium americanum. II. Substrate interaction and product inhibition studies of flavonol 3-, 6-, and 4'-O-methyltransferases. Arch. Biochem. Biophys. 238 (1985) 606-618. [PMID: 3994394]

[EC 2.1.1.83 created 1989]


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