EC - L-galactonolactone dehydrogenase

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IntEnz Enzyme Nomenclature


Accepted name:
L-galactonolactone dehydrogenase
Other names:
L-galactono-γ-lactone dehydrogenase
galactonolactone dehydrogenase
L-galactono-γ-lactone:ferricytochrome-c oxidoreductase
Systematic name:
L-galactono-1,4-lactone:ferricytochrome-c oxidoreductase



This enzyme catalyses the final step in the biosynthesis of L-ascorbic acid in higher plants and in nearly all higher animals with the exception of primates and some birds [5]. The enzyme is very specific for its substrate L-galactono-1,4-lactone as D-galactono-γ-lactone, D-gulono-γ-lactone, L-gulono-γ-lactone, D-erythronic-γ-lactone, D-xylonic-γ-lactone, L-mannono-γ-lactone, D-galactonate, D-glucuronate and D-gluconate are not substrates [5]. FAD, NAD+, NADP+ and O2 (cf. EC, L-galactonolactone oxidase) cannot act as electron acceptor [5].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0016633
CAS Registry Number: 9029-02-1


  1. Mapson, L.W. and Breslow, E.
    Properties of partially purified L-galactono-γ-lactone dehydrogenase.
    Biochem. J. 65 : 29P (1957).
  2. Mapson, L.W., Isherwood, F.A. and Chen, Y.T.
    Biological synthesis of L-ascorbic acid: the conversion of L-galactono-γ-lactone into L-ascorbic acid by plant mitochondria.
    Biochem. J. 56 : 21-28 (1954). [PMID: 13126087]
  3. Isherwood, F.A., Chen, Y.T. and Mapson, L.W.
    Synthesis of L-ascorbic acid in plants and animals.
    Biochem. J. 56 : 1-15 (1954). [PMID: 13126085]
  4. Ôba, K., Ishikawa, S., Nishikawa, M., Mizuno, H. and Yamamoto, T.
    Purification and properties of L-galactono-γ-lactone dehydrogenase, a key enzyme for ascorbic acid biosynthesis, from sweet potato roots.
    J. Biochem. 117 : 120-124 (1995). [PMID: 7775377]
  5. Østergaard, J., Persiau, G., Davey, M.W., Bauw, G. and Van Montagu, M.
    Isolation of a cDNA coding for L-galactono-γ-lactone dehydrogenase, an enzyme involved in the biosynthesis of ascorbic acid in plants. Purification, characterization, cDNA cloning, and expression in yeast.
    J. Biol. Chem. 272 : 30009-30016 (1997). [PMID: 9374475]

[EC created 1961, modified 2006]