title: Isolation and characterization of glycolic acid dehydrogenase from human liver.
abstract: Glycolic acid dehydrogenase has been purified over 800-fold from human liver by (NH4)2SO4 fractionation and column chromatography with DEAE-cellulose and hydroxyapatite. The enzyme catalyzes the direct oxidation of glycolate to oxalate without forming glyoxylate as a free intermediate. Activity is found only in the liver in the soluble fraction. The enzyme is specific for glycolate and inhibits no activity towards glycine or glyoxylate. Glyoxylate and DL-phenyllactate exhibit the enzyme. Optimum activity occurs sharply at pH 6.1 and the Michaelis constant for glycolate was 6.3.10(-5)M. Molecular oxygen does not appear to be the electron acceptor and no requirement for cofactors has been demonstrated, althoug flavin mononucleotide, ascorbate and cytochrome c stimulate activity. The isolation of this enzyme which may account for a significant part of the normal oxalate excretion in man, provides a more complete understanding of the pathways of oxalate biosynthesis and must be taken into account when considering possible methods for controlling disorders of oxalate metabolism.
mesh_terms: D000429:Alcohol Oxidoreductases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D001205:Ascorbic Acid / Q000494:pharmacology; D003574:Cytochrome c Group / Q000494:pharmacology; D005486:Flavin Mononucleotide / Q000494:pharmacology; D006016:Glycolates / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008970:Molecular Weight; D010070:Oxalates / Q000378:metabolism
chemical_list: D003574:Cytochrome c Group; D006016:Glycolates; D010070:Oxalates; D005486:Flavin Mononucleotide; D000429:Alcohol Oxidoreductases; C020819:glycolic acid dehydrogenase; D001205:Ascorbic Acid