Reaction: (1) a (2S,3R)-flavan-3-ol + 2 NADP+ = an anthocyanidin with a 3-hydroxy group + 2 NADPH + H+
(2) a (2S,3S)-flavan-3-ol + 2 NADP+ = an anthocyanidin with a 3-hydroxy group + 2 NADPH + H+
Systematic name: (2S)-flavan-3-ol:NAD(P)+ oxidoreductase
Comments: The enzyme, characterized from Vitis vinifera (grape), participates in the flavonoid biosynthesis pathway. It catalyses the double reduction of anthocyanidins, producing a mixture of (2S,3S)- and (2S,3R)-flavan-3-ols. The enzyme catalyses sequential hydride transfers to C-2 and C-4, respectively. Epimerization at C-3 is achieved by tautomerization that occurs between the two hydride transfers. cf. EC 1.3.1.77, anthocyanidin reductase [(2R,3R)-flavan-3-ol-forming].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number:
References:
1. Gargouri, M., Manigand, C., Mauge, C., Granier, T., Langlois d'Estaintot, B., Cala, O., Pianet, I., Bathany, K., Chaudiere, J. and Gallois, B. Structure and epimerase activity of anthocyanidin reductase from Vitis vinifera. Acta Crystallogr. D Biol. Crystallogr. 65 (2009) 989-1000. [PMID: 19690377]
2. Gargouri, M., Chaudiere, J., Manigand, C., Mauge, C., Bathany, K., Schmitter, J.M. and Gallois, B. The epimerase activity of anthocyanidin reductase from Vitis vinifera and its regiospecific hydride transfers. Biol. Chem. 391 (2010) 219-227. [PMID: 20030585]