Entry
Name
quercetin 3-O-methyltransferase;
flavonol 3-O-methyltransferase;
flavonoid 3-methyltransferase
Class
Transferases;
Transferring one-carbon groups;
Methyltransferases
BRITE hierarchy
Sysname
S-adenosyl-L-methionine:3,5,7,3',4'-pentahydroxyflavone 3-O-methyltransferase
Reaction(IUBMB)
S-adenosyl-L-methionine + 3,5,7,3',4'-pentahydroxyflavone = S-adenosyl-L-homocysteine + 3-methoxy-5,7,3',4'-tetrahydroxyflavone [RN:
R02157 ]
Reaction(KEGG)
Substrate
S-adenosyl-L-methionine [CPD:
C00019 ];
3,5,7,3',4'-pentahydroxyflavone [CPD:
C00389 ]
Product
S-adenosyl-L-homocysteine [CPD:
C00021 ];
3-methoxy-5,7,3',4'-tetrahydroxyflavone [CPD:
C04443 ]
Comment
Specific for quercetin. Related enzymes bring about the 3-O-methylation of other flavonols, such as galangin and kaempferol.
History
EC 2.1.1.76 created 1984
Pathway
ec00944 Flavone and flavonol biosynthesis
ec01110 Biosynthesis of secondary metabolites
Orthology
K05279 flavonol 3-O-methyltransferase
Reference
1
Authors
De Luca V, Brunet G, Khouri H, Ibrahim R, Hrazdina G.
Title
Flavonol 3-O-methyltransferase in plant-tissues.
Journal
Z Naturforsch 37:134-135 (1982)
Reference
Authors
De Luca V, Ibrahim RK
Title
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.
Journal
Reference
Authors
De Luca V, Ibrahim RK.
Title
Enzymatic synthesis of polymethylated flavonols in Chrysosplenium americanum. II. Substrate interaction and product inhibition studies of flavonol 3-, 6-, and 4'-O-methyltransferases.
Journal
Reference
4
Authors
Ibrahim RK, De Luca V.
Title
Polymethylated flavonol synthesis is catalyzed by distinct O-methyltransferases.
Journal
Naturwissenschaften 69:41-42 (1982)
Other DBs
ExplorEnz - The Enzyme Database: 2.1.1.76
ExPASy - ENZYME nomenclature database: 2.1.1.76