IUBMB Enzyme Nomenclature

EC 1.14.11.23

Accepted name: flavonol synthase

Reaction: a dihydroflavonol + 2-oxoglutarate + O2 = a flavonol + succinate + CO2 + H2O

See diagram for reaction in quercetin or kaempferol or myricetin biosynthesis.

Other Name(s): flavonoid 2-oxoglutarate-dependent dioxygenase; FLS

Systematic name: dihydroflavonol,2-oxoglutarate:oxygen oxidoreductase

Comments: In addition to the desaturation of (2R,3R)-dihydroflavonols to flavonols, the enzyme from the satsuma Citrus unshiu also has a non-specific activity that trans-hydroxylates the flavanones (2S)-naringenin and the unnatural (2R)-naringenin at C-3 to kaempferol and (2R,3R)-dihydrokaempferol, respectively [2]. Requires Fe2+.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 146359-76-4

References: (if your browser cannot recognise unicode the author is Lukacin with a hacek over the c)

1. Wellmann, F., Lukačin, R., Moriguchi, T., Britsch, L., Schiltz, E. and Matern, U. Functional expression and mutational analysis of flavonol synthase from Citrus unshiu. Eur. J. Biochem. 269 (2002) 4134-4142. [PMID: 12180990]

2. Lukačin, R., Wellmann, F., Britsch, L., Martens, S. and Matern, U. Flavonol synthase from Citrus unshiu is a bifunctional dioxygenase. Phytochemistry 62 (2003) 287-292. [PMID: 12620339]

3. Martens, S., Forkmann, G., Britsch, L., Wellmann, F., Matern, U. and Lukačin, R. Divergent evolution of flavonoid 2-oxoglutarate-dependent dioxygenases in parsley. FEBS Lett. 544 (2003) 93-98. [PMID: 12782296]

4. Turnbull, J.J., Nakajima, J., Welford, R.W., Yamazaki, M., Saito, K. and Schofield, C.J. Mechanistic studies on three 2-oxoglutarate-dependent oxygenases of flavonoid biosynthesis: anthocyanidin synthase, flavonol synthase, and flavanone 3β-hydroxylase. J. Biol. Chem. 279 (2004) 1206-1216. [PMID: 14570878]

[EC 1.14.11.23 created 2004]


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