Reaction: a (2R,3S,4S)-leucoanthocyanidin + NADP+ = a (2R,3R)-dihydroflavonol + NADPH + H+
For diagram of reaction click here.
Other name(s): dihydrokaempferol 4-reductase; dihydromyricetin reductase; NADPH-dihydromyricetin reductase; dihydroquercetin reductase; DFR (gene name), dihydroflavanol 4-reductase (incorrect)
Systematic name: (2R,3S,4S)-leucoanthocyanidin:NADP+ 4-oxidoreductase
Comments: This plant enzyme, involved in the biosynthesis of anthocyanidins, is known to act on (+)-dihydrokaempferol, (+)-taxifolin, and (+)-dihydromyricetin, although some enzymes may act only on a subset of these compounds. Each dihydroflavonol is reduced to the corresponding cis-flavan-3,4-diol. NAD+ can act instead of NADP+, but more slowly.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 83682-99-9
References:
1. Heller, W., Forkmann, G., Britsch, L. and Grisebach, H. Enzymatic reduction of (+)-dihydroflavonols to flavan-3,4-cis- diols with flower extracts from Matthiola incana and its role in anthocyanin biosynthesis. Planta 165 (1985) 284-287.
2. Stafford, H.A. and Lester, H.H. Flavan-3-ol biosynthesis the conversion of (+)-dihydromyricetin to its flavan-3,4-diol (leucodelphinidin) and to (+)-gallocatechin by reductases extracted from tissue-cultures of Ginkgo biloba and Pseudotsuga-menziesii. Plant Physiol. 78 (1985) 791-794. [PMID: 16664326]
3. Fischer, D., Stich, K., Britsch, L. and Grisebach, H. Purification and characterization of (+)-dihydroflavonol (3-hydroxyflavanone) 4-reductase from flowers of Dahlia variabilis. Arch. Biochem. Biophys. 264 (1988) 40-47. [PMID: 3293532]
4. Li, H., Qiu, J., Chen, F., Lv, X., Fu, C., Zhao, D., Hua, X. and Zhao, Q. Molecular characterization and expression analysis of dihydroflavonol 4-reductase (DFR) gene in Saussurea medusa. Mol. Biol. Rep. 39 (2012) 2991-2999. [PMID: 21701830]