EC 220.127.116.11 - L-galactonolactone dehydrogenase
IntEnz Enzyme Nomenclature
- (1) L-galactono-1,4-lactone + 4 ferricytochrome c = L-dehydroascorbate + 4 ferrocytochrome c + 4 H+
- (1a) L-galactono-1,4-lactone + 2 ferricytochrome c = L-ascorbate + 2 ferrocytochrome c + 2 H+
- (1b) L-ascorbate + 2 ferricytochrome c = L-dehydroascorbate + 2 ferrocytochrome c + 2 H+ (spontaneous)
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 . 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 . FAD, NAD+, NADP+ and O2 (cf. EC 18.104.22.168, L-galactonolactone oxidase) cannot act as electron acceptor .
Links to other databases
Properties of partially purified L-galactono-γ-lactone dehydrogenase.Biochem. J. 65 : 29P (1957).
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]
Synthesis of L-ascorbic acid in plants and animals.Biochem. J. 56 : 1-15 (1954). [PMID: 13126085]
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]
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 22.214.171.124 created 1961, modified 2006]