Oxidoreductases;
Acting on the CH-CH group of donors;
With NAD+ or NADP+ as acceptor
Sysname
(2S)-flavan-3-ol:NAD(P)+ oxidoreductase
Reaction(IUBMB)
(1) a (2S,3R)-flavan-3-ol + 2 NADP+ = an anthocyanidin with a 3-hydroxy group + 2 NADPH + H+ [RN:R11426];
(2) a (2S,3S)-flavan-3-ol + 2 NADP+ = an anthocyanidin with a 3-hydroxy group + 2 NADPH + H+ [RN:R11427]
anthocyanidin with a 3-hydroxy group [CPD:C21381];
NADPH [CPD:C00005];
H+ [CPD:C00080]
Comment
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].
