Anthocyanidin reductases from Medicago truncatula and Arabidopsis thaliana

Arch Biochem Biophys. 2004 Feb 1;422(1):91-102. doi: 10.1016/


Anthocyanidin reductase (ANR), encoded by the BANYULS gene, is a newly discovered enzyme of the flavonoid pathway involved in the biosynthesis of condensed tannins. ANR functions immediately downstream of anthocyanidin synthase to convert anthocyanidins into the corresponding 2,3-cis-flavan-3-ols. We report the biochemical properties of ANRs from the model legume Medicago truncatula (MtANR) and the model crucifer Arabidopsis thaliana (AtANR). Both enzymes have high temperature optima. MtANR uses both NADPH and NADH as reductant with slight preference for NADPH over NADH. In contrast, AtANR only uses NADPH and exhibits positive cooperativity for the co-substrate. MtANR shows preference for potential anthocyanidin substrates in the order cyanidin>pelargonidin>delphinidin, with typical Michaelis-Menten kinetics for each substrate. In contrast, AtANR exhibits the reverse preference, with substrate inhibition at high concentrations of cyanidin and pelargonidin. (+)-Catechin and (+/-)-dihydroquercetin inhibit AtANR but not MtANR, whereas quercetin inhibits both enzymes. Possible catalytic reaction sequences for ANRs are discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Anthocyanins / metabolism*
  • Arabidopsis / enzymology*
  • Flavonoids / biosynthesis
  • Flavonoids / chemistry
  • Flavonoids / pharmacology
  • Hydrogen-Ion Concentration
  • Kinetics
  • Medicago / enzymology*
  • Molecular Sequence Data
  • NAD / metabolism
  • NADH, NADPH Oxidoreductases / chemistry
  • NADH, NADPH Oxidoreductases / genetics
  • NADH, NADPH Oxidoreductases / metabolism*
  • NADP / metabolism
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Substrate Specificity
  • Tannins / biosynthesis
  • Temperature


  • Anthocyanins
  • Flavonoids
  • Recombinant Fusion Proteins
  • Tannins
  • NAD
  • flavan-3-ol
  • NADP
  • NADH, NADPH Oxidoreductases