Reaction: S-adenosyl-L-methionine + 5,7,3',4'-tetrahydroxy-3-methoxyflavone = S-adenosyl-L-homocysteine + 5,3',4'-trihydroxy-3,7-dimethoxyflavone
For diagram click here.
Other name(s): flavonol 7-O-methyltransferase; flavonol 7-methyltransferase; 7-OMT; S-adenosyl-L-methionine:3',4',5,7-tetrahydroxy-3-methoxyflavone 7-O-methyltransferase; 3-methylquercitin 7-O-methyltransferase [mis-spelt]
Systematic name: S-adenosyl-L-methionine:5,7,3',4'-tetrahydroxy-3-methoxyflavone 7-O-methyltransferase
Comments: Involved with EC 2.1.1.76 quercetin 3-O-methyltransferase and EC 2.1.1.83 3,7-dimethylquercetin 4'-O-methyltransferase in the methylation of quercitin 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: 97089-67-3
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]