ID 1.3.1.77 DE anthocyanidin reductase [(2R,3R)-flavan-3-ol-forming]. AN ANR. AN anthocyanidin reductase. CA (1) a (2R,3R)-flavan-3-ol + 2 NAD(+) = an anthocyanidin with a 3-hydroxy CA group + 2 H(+) + 2 NADH. CA (2) a (2R,3R)-flavan-3-ol + 2 NADP(+) = an anthocyanidin with a 3-hydroxy CA group + 2 H(+) + 2 NADPH. CC -!- The enzyme participates in the flavonoid biosynthesis pathway found CC in plants. CC -!- It catalyzes the double reduction of anthocyanidins, producing CC (2R,3R)-flavan-3-ol monomers required for the formation of CC proanthocyanidins. CC -!- While the enzyme from the legume Medicago truncatula can use both CC NADPH and NADH as reductant, that from the crucifer Arabidopsis CC thaliana uses only NADPH. CC -!- Also, while the substrate preference of the M. truncatula is CC cyanidin>pelargonidin>delphinidin, the reverse preference is found CC with the Arabidopsis enzyme. cf. EC 1.3.1.112. DR Q9SEV0, BAN_ARATH ; //