Oxidoreductases;
Acting on paired donors, with incorporation or reduction of molecular oxygen;
With 2-oxoglutarate as one donor, and incorporation of one atom of oxygen into each donor

(2R,3S,4S)-leucoanthocyanidin,2-oxoglutarate:oxygen oxidoreductase

a (2R,3S,4S)-leucoanthocyanidin + 2-oxoglutarate + O2 = an anthocyanidin + succinate + CO2 + 2 H2O (overall reaction) [RN:R05723 R07366];
(1a) a (2R,3S,4S)-leucoanthocyanidin + 2-oxoglutarate + O2 = a (4S)- 2,3-dehydroflavan-3,4-diol + succinate + CO2 + H2O;
(1b) a (4S)- 2,3-dehydroflavan-3,4-diol = an anthocyanidin + H2O

R05723 R07366;
(other) R04276 R05036 R05037 R06540

(2R,3S,4S)-leucoanthocyanidin [CPD:C21418];
2-oxoglutarate [CPD:C00026];
O2 [CPD:C00007];
(4S)- 2,3-dehydroflavan-3,4-diol

The enzyme requires Fe(II) and ascorbate. It is involved in the pathway by which many flowering plants make anthocyanin flower pigments (glycosylated anthocyandins). The enzyme hydroxylates the C-3 carbon, followed by a trans diaxial elimination, forming a C-2,C-3 enol. The product loses a second water molecule to form anthocyanidins. When assayed in vitro, non-enzymic epimerization of the product can lead to formation of dihydroflavanols. Thus when the substrate is leucocyanidin, a mixture of (+)-taxifolin and (+)-epitaxifolin are formed. The enzyme can also oxidize the formed (+)-taxifolin to quercetin (cf. EC 1.14.11.23, flavonol synthase) [2,3].

EC 1.14.11.19 created 2001, modified 2017

1  [PMID:10074715]

Saito K, Kobayashi M, Gong Z, Tanaka Y, Yamazaki M.

Direct evidence for anthocyanidin synthase as a 2-oxoglutarate-dependent oxygenase: molecular cloning and functional expression of cDNA from a red forma of Perilla frutescens.

Plant. J. 17 (1999) 181-9.

[ag:BAA20143]

2

Turnbull, J.J., Sobey, W.J., Aplin, R.T., Hassan, A., Firmin, J.L., Schofield, C.J. and Prescott, A.G.

Are anthocyanidins the immediate products of anthocyanidin synthase?.

Chem. Commun. (2000) 2473-2474.

3  [PMID:11796114]

Wilmouth RC, Turnbull JJ, Welford RW, Clifton IJ, Prescott AG, Schofield CJ

Structure and mechanism of anthocyanidin synthase from Arabidopsis thaliana.

Structure. 10 (2002) 93-103.

[ath:AT4G22880]

4  [PMID:14552794]

Turnbull JJ, Nagle MJ, Seibel JF, Welford RW, Grant GH, Schofield CJ

The C-4 stereochemistry of leucocyanidin substrates for anthocyanidin synthase affects product selectivity.

Bioorg. Med. Chem. Lett. 13 (2003) 3853-7.

5  [PMID:16494872]

Wellmann F, Griesser M, Schwab W, Martens S, Eisenreich W, Matern U, Lukacin R

Anthocyanidin synthase from Gerbera hybrida catalyzes the conversion of (+)-catechin to cyanidin and a novel procyanidin.

FEBS. Lett. 580 (2006) 1642-8.