EC - Aureusidin synthase

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IntEnz Enzyme Nomenclature


Accepted name:
aureusidin synthase
Other name:
Systematic name:
2',4,4',6'-tetrahydroxychalcone 4'-O-β-glucoside:oxygen oxidoreductase




A copper-containing glycoprotein that plays a key role in the yellow coloration of flowers such as Antirrhinum majus (snapdragon). The enzyme is a homologue of plant polyphenol oxidase [1] and catalyses two separate chemical transformations, i.e. 3-hydroxylation and oxidative cyclization (2',-dehydrogenation). H2O2 activates reaction (1) but inhibits reaction (2). Originally considered to act on the phenol but now thought to mainly act on the 4'-O-β-glucoside in vivo [4].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0102791
CAS Registry Number: 320784-48-3


  1. Nakayama, T., Yonekura-Sakakibara, K., Sato, T., Kikuchi, S., Fukui, Y., Fukuchi-Mizutani, M., Ueda, T., Nakao, M., Tanaka, Y., Kusumi, T. and Nishino, T.
    Aureusidin synthase: A polyphenol oxidase homolog responsible for flower coloration.
    Science 290: 1163-1166 (2000). [PMID: 11073455]
  2. Nakayama, T., Sato, T., Fukui, Y., Yonekura-Sakakibara, K., Hayashi, H., Tanaka, Y., Kusumi, T. and Nishino, T.
    Specificity analysis and mechanism of aurone synthesis catalyzed by aureusidin synthase, a polyphenol oxidase homolog responsible for flower coloration.
    FEBS Lett. 499: 107-111 (2001). [PMID: 11418122]
  3. Sato, T., Nakayama, T., Kikuchi, S., Fukui, Y., Yonekura-Sakakibara, K., Ueda, T., Nishino, T., Tanaka, Y. and Kusumi, T.
    Enzymatic formation of aurones in the extracts of yellow snapdragon flowers.
    Plant Sci. 160: 229-236 (2001). [PMID: 11164594]
  4. Ono, E., Fukuchi-Mizutani, M., Nakamura, N., Fukui, Y., Yonekura-Sakakibara, K., Yamaguchi, M., Nakayama, T., Tanaka, T., Kusumi, T., Tanaka, Y.
    Yellow flowers generated by expression of the aurone biosynthetic pathway.
    Proc. Natl. Acad. Sci. U.S.A. 103: 11075-11080 (2006). [PMID: 16832053]

[EC created 2003, modified 2012]