L-galactonolactone dehydrogenase (
EC1.3.2.3, galactonolactone dehydrogenase, L-galactono-gamma-lactone dehydrogenase, L-galactono-gamma-lactone:ferricytochrome-c oxidoreductase, GLDHase, GLDase) is an
enzyme with
systematic nameL-galactono-1,4-lactone:ferricytochrome-c oxidoreductase.[1][2][3][4][5] This enzyme
catalyses the following
chemical reaction
(1) L-galactono-1,4-lactone + 2 ferricytochrome c L-ascorbate + 2 ferrocytochrome c + 2 H+
(2) 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
plants and other photosynthetic eukaryotes.[6]
References
^Mapson, L.W.; Breslow, E. (1957). "Properties of partially purified L-galactono-γ-lactone dehydrogenase". Biochem. J. 65: 29.
^Oba K, Ishikawa S, Nishikawa M, Mizuno H, Yamamoto T (January 1995). "Purification and properties of L-galactono-gamma-lactone dehydrogenase, a key enzyme for ascorbic acid biosynthesis, from sweet potato roots". Journal of Biochemistry. 117 (1): 120–4.
doi:
10.1093/oxfordjournals.jbchem.a124697.
PMID7775377.