Reaction: (1) S-adenosyl-L-methionine + a 3'-hydroxyflavonoid = S-adenosyl-L-homocysteine + a 3'-methoxyflavonoid
(2) S-adenosyl-L-methionine + a 5'-hydroxy-3'-methoxyflavonoid = S-adenosyl-L-homocysteine + a 3',5'-dimethoxyflavonoid
For diagram of reaction click here.
Glossary: delphinidin = 3,3',4',5,5',7-hexahydroxyflavylium
cyanidin = 3,3',4',5,7-pentahydroxyflavylium
myricetin = 3,3',4',5,5',7-hexahydroxyflavone
quercetin = 3,3',4',5,7-pentahydroxyflavone
Other name(s): AOMT; CrOMT2
Systematic name: S-adenosyl-L-methionine:flavonoid 3'-O-methyltransferase
Comments: Isolated from Vitis vinifera (grape) . Most active with delphinidin 3-glucoside but also acts on cyanidin 3-glucoside, cyanidin, myricetin, quercetin and quercetin 3-glucoside. The enzyme from Catharanthus roseus was most active with myricetin .
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
1. Cacace, S., Schröder, G., Wehinger, E., Strack, D., Schmidt, J. and Schröder, J. A flavonol O-methyltransferase from Catharanthus roseus performing two sequential methylations. Phytochemistry 62 (2003) 127-137. [PMID: 12482447]
2. Hugueney, P., Provenzano, S., Verries, C., Ferrandino, A., Meudec, E., Batelli, G., Merdinoglu, D., Cheynier, V., Schubert, A. and Ageorges, A. A novel cation-dependent O-methyltransferase involved in anthocyanin methylation in grapevine. Plant Physiol. 150 (2009) 2057-2070. [PMID: 19525322]