EC - L-gulonolactone oxidase

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IntEnz Enzyme Nomenclature


Accepted name:
L-gulonolactone oxidase
Other names:
L-gulono-γ-lactone oxidase
L-gulono-γ-lactone:O2 oxidoreductase
Systematic name:
L-gulono-1,4-lactone:oxygen 3-oxidoreductase




A flavoprotein (FAD). The product spontaneously isomerizes to L-ascorbate. While most higher animals can synthesize ascorbic acid, primates and guinea pigs cannot [3].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Protein domains and families: PROSITE:PDOC00674
Structural data: CSA , EC2PDB
Gene Ontology: GO:0050105
CAS Registry Number: 9028-78-8
UniProtKB/Swiss-Prot: (12) [show] [UniProt]


  1. Isherwood, F.A., Mapson, L.W. and Chen, Y.T.
    Synthesis of L-ascorbic acid in rat liver homogenates. Conversion of L-gulono- and L-galactono-γ-lactone and the respective acids into L-ascorbic acid.
    Biochem. J. 76 : 157-171 (1960). [PMID: 14405898]
  2. Kiuchi, K., Noshikimi, M. and Yagi, K.
    Purification and characterization of L-gulonolactone oxidase from chicken kidney microsomes.
    Biochemistry 21 : 5076 (1982). [PMID: 7138847]
  3. Nishikimi, M., Fukuyama, R., Minoshima, S., Shimizu, N. and Yagi, K.
    Cloning and chromosomal mapping of the human nonfunctional gene for L-gulono-γ-lactone oxidase, the enzyme for L-ascorbic acid biosynthesis missing in man.
    J. Biol. Chem. 269 : 13685-13688 (1994). [PMID: 8175804]
  4. Chatterjee, I.B., Chatterjee, G.C., Ghosh, N.C. and Guha, B.C.
    Identification of 2-keto-L-gulonolactone as an intermediate in the biosynthesis of L-ascorbic acid.
    Naturwissenschaften 46 : 475 (1959).

[EC created 1965, modified 2001, modified 2006]