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 188.8.131.52 quercetin 3-O-methyltransferase and EC 184.108.40.206 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
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]