Ostergaard J, Persiau G, Davey MW, Bauw G, Van Montagu M
Title
Isolation of a cDNA coding for L-galactono-gamma-lactone dehydrogenase, an enzyme involved in the biosynthesis of ascorbic acid in plants. Purification, characterization, cDNA cloning, and expression in yeast.
L-galactono-1,4-lactone [CPD:C01115];
ferricytochrome c [CPD:C00125];
L-ascorbate [CPD:C00072]
Product
L-dehydroascorbate [CPD:C05422];
ferrocytochrome c [CPD:C00126];
H+ [CPD:C00080];
L-ascorbate [CPD:C00072]
Comment
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-gamma-lactone, D-gulono-gamma-lactone, L-gulono-gamma-lactone, D-erythronic-gamma-lactone, D-xylonic-gamma-lactone, L-mannono-gamma-lactone, D-galactonate, D-glucuronate and D-gluconate are not substrates [5]. FAD, NAD+, NADP+ and O2 (cf. EC 1.3.3.12, L-galactonolactone oxidase) cannot act as electron acceptor [5].
Ostergaard J, Persiau G, Davey MW, Bauw G, Van Montagu M
Title
Isolation of a cDNA coding for L-galactono-gamma-lactone dehydrogenase, an enzyme involved in the biosynthesis of ascorbic acid in plants. Purification, characterization, cDNA cloning, and expression in yeast.
Enzymatic reactions [BR:br08201]
1. Oxidoreductase reactions
1.3 Acting on the CH-CH group of donors
1.3.2 With a cytochrome as acceptor
1.3.2.3
R00640 L-Galactono-1,4-lactone + 2 Ferricytochrome c <=> Ascorbate + 2 Ferrocytochrome c + 2 H+
