Molecular basis for the deficiency in humans of gulonolactone oxidase, a key enzyme for ascorbic acid biosynthesis.
The inability of humans to synthesize L-ascorbic acid is known to be due to a lack of L-gulono-gamma-lactone oxidase, an enzyme that is required for the biosynthesis of this vitamin. Isolation of a cDNA for rat L-gulono-gamma-lactone oxidase allowed us to study the basic defect underlying this deficiency at the gene level and led to isolation of a human genomic clone related to L-gulono-gamma-lactone oxidase as well as three overlapping clones covering the entire coding region of the rat L-gulono-gamma-lactone oxidase cDNA. Sequence analysis study indicated that the human L-gulono-gamma-lactone oxidase gene has accumulated a large number of mutations since it stopped being active and that it now exists as a pseudogene in the human genome.
Nishikimi
M
M
Institute of Applied Biochemistry, Yagi Memorial Park, Gifu, Japan.
Yagi
K
K
D001205:Ascorbic Acid / Q000096:biosynthesis*; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D005796:Genes; D006801:Humans; D050544:L-Gulonolactone Oxidase; D008967:Molecular Biology; D008969:Molecular Sequence Data; D013401:Sugar Alcohol Dehydrogenases / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism
D004247:DNA; D013401:Sugar Alcohol Dehydrogenases; D050544:L-Gulonolactone Oxidase; D001205:Ascorbic Acid