Reaction: (2R,3S)-catechin + NADP+ + H2O = 2,3-trans-3,4-cis-leucocyanidin + NADPH + H+
For diagram click here.
Other name(s): leucocyanidin reductase
Systematic name: (2R,3S)-catechin:NADP+ 4-oxidoreductase
Comments: The enzyme catalyses the synthesis of catechin, catechin-4β-ol (leucocyanidin) and the related flavan-3-ols afzelechin and gallocatechin, which are initiating monomers in the synthesis of plant polymeric proanthocyanidins or condensed tannins. While 2,3-trans-3,4-cis-leucocyanidin is the preferred flavan-3,4-diol substrate, 2,3-trans-3,4-cis-leucodelphinidin and 2,3-trans-3,4-cis-leucopelargonidin can also act as substrates, but more slowly. NADH can replace NADPH but is oxidized more slowly.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 776323-46-7
References:
1. Tanner, G.J. and Kristiansen, K.N. Synthesis of 3,4-cis-[3H]leucocyanidin and enzymatic reduction to catechin. Anal. Biochem. 209 (1993) 274-277. [PMID: 8470799]
2. Tanner, G.J., Francki, K.T., Abrahams, S., Watson, J.M., Larkin, P.J. and Ashton, A.R. Proanthocyanidin biosynthesis in plants: Purification of legume leucoanthocyanidin reductase and molecular cloning of its cDNA. J. Biol. Chem. 278 (2003) 31647-31656. [PMID: 12788945]