EC - Anthocyanidin synthase

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IntEnz Enzyme Nomenclature


Accepted name:
anthocyanidin synthase
Other names:
leucoanthocyanidin dioxygenase
leucocyanidin oxygenase
leucocyanidin,2-oxoglutarate:oxygen oxidoreductase
ANS (gene name)
Systematic name:
(2R,3S,4S)-leucoanthocyanidin,2-oxoglutarate:oxygen oxidoreductase




The enzyme requires Fe(II) and ascorbate. It is involved in the pathway by which many flowering plants make anthocyanin flower pigments (glycosylated anthocyandins). The enzyme hydroxylates the C-3 carbon, followed by a trans diaxial elimination, forming a C-2,C-3 enol. The product loses a second water molecule to form anthocyanidins. When assayed in vitro, non-enzymic epimerization of the product can lead to formation of dihydroflavanols. Thus when the substrate is leucocyanidin, a mixture of (+)-taxifolin and (+)-epitaxifolin are formed. The enzyme can also oxidize the formed (+)-taxifolin to quercetin (cf. EC, flavonol synthase) [2,3].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Protein domains and families: PROSITE:PDOC51471
Structural data: CSA , EC2PDB
Gene Ontology: GO:0050589
CAS Registry Number: 180984-01-4
UniProtKB/Swiss-Prot: (10) [show] [UniProt]


  1. Saito, K., Kobayashi, M., Gong, Z., Tanaka, Y. and Yamazaki, M.
    Direct evidence for anthocyanidin synthase as a 2-oxoglutarate-dependent oxygenase: molecular cloning and functional expression of cDNA from a red forma of Perilla frutescens.
    Plant J. 17 : 181-190 (1999). [PMID: 10074715]
  2. Turnbull, J.J., Sobey, W.J., Aplin, R.T., Hassan, A., Firmin, J.L., Schofield, C.J. and Prescott, A.G.
    Are anthocyanidins the immediate products of anthocyanidin synthase?
    Chem. Commun. 2473-2474 (2000).
  3. Wilmouth, R. C., Turnbull, J. J., Welford, R. W., Clifton, I. J., Prescott, A. G., Schofield, C. J.
    Structure and mechanism of anthocyanidin synthase from Arabidopsis thaliana.
    Structure 10 : 93-103 (2002). [PMID: 11796114]
  4. Turnbull, J. J., Nagle, M. J., Seibel, J. F., Welford, R. W., Grant, G. H., Schofield, C. J.
    The C-4 stereochemistry of leucocyanidin substrates for anthocyanidin synthase affects product selectivity.
    Bioorg. Med. Chem. Lett. 13 : 3853-3857 (2003). [PMID: 14552794]
  5. Wellmann, F., Griesser, M., Schwab, W., Martens, S., Eisenreich, W., Matern, U., Lukacin, R.
    Anthocyanidin synthase from Gerbera hybrida catalyzes the conversion of (+)-catechin to cyanidin and a novel procyanidin.
    FEBS Lett. 580 : 1642-1648 (2006). [PMID: 16494872]

[EC created 2001 as EC, transferred 2018 to EC]