|Superclasses:||Reactions Classified By Conversion Type → Simple Reactions → Chemical Reactions|
|Reactions Classified By Substrate → Small-Molecule Reactions|
EC Number: 220.127.116.11
Enzymes and Genes:
|Arabidopsis thaliana col :||flavonol synthase
|Citrus unshiu :||flavonol synthase/flavanone 3-dioxygenase
|Equisetum arvense :||flavonol synthase
|Fagopyrum tataricum :||flavonol synthase
|Ginkgo biloba :||anthocyanidin synthase/flavonol synthase
Note that this reaction equation differs from the official Enzyme Commission reaction equation for this EC number, which can be found here .
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.
Mass balance status: Balanced.
Direct generic reaction:
a dihydroflavonol + 2-oxoglutarate + oxygen → a flavonol + succinate + CO2 + H2O (18.104.22.168)
Enzyme Commission Primary Name: flavonol synthase
Standard Gibbs Free Energy (ΔrG'° in kcal/mol): -139.58595 [Latendresse13]
Enzyme Commission Summary:
In addition to the desaturation of (2R,3R)-dihydroflavonols to flavonols, the enzyme from the satsuma orange 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 (+)-dihydrokaempferol, respectively [Lukacin03]. Requires Fe2+.
Unification Links: KEGG:R02160
Martens03: Martens S, Forkmann G, Britsch L, Wellmann F, Matern U, Lukacin R (2003). "Divergent evolution of flavonoid 2-oxoglutarate-dependent dioxygenases in parsley." FEBS Lett 544(1-3);93-8. PMID: 12782296
Turnbull04: Turnbull JJ, Nakajima J, Welford RW, Yamazaki M, Saito K, Schofield CJ (2004). "Mechanistic studies on three 2-oxoglutarate-dependent oxygenases of flavonoid biosynthesis: anthocyanidin synthase, flavonol synthase, and flavanone 3beta-hydroxylase." J Biol Chem 279(2);1206-16. PMID: 14570878
Wellmann02: Wellmann F, Lukacin R, Moriguchi T, Britsch L, Schiltz E, Matern U (2002). "Functional expression and mutational analysis of flavonol synthase from Citrus unshiu." Eur J Biochem 269(16);4134-42. PMID: 12180990
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