Superoxide dismutases enhance the rate of autoxidation of 3-hydroxyanthranilic acid.
The autoxidation of 3-hydroxyanthranilate to cinnabarinate at 37 degrees C and at pH 7.4 is hastened by superoxide dismutase (SOD). The Cu,Zn-containing enzyme from bovine erythrocytes and the Mn-containing enzyme from Escherichia coli were equally effective in this regard; whereas the H2O2-inactivated Cu,Zn enzyme was ineffective. Catalase appears to augment the effect of superoxide dismutase, because it prevents the bleaching of cinnabarinate by H2O2. It follows that O2-, which is a product of the autoxidation, slows the net autoxidation by engaging in back reactions and that SOD increases the rate of autoxidation by removal of O2- and thus by prevention of these back reactions.
Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710.
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Ishii
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Iwahashi
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Sugata
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Kido
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Fridovich
D015095:3-Hydroxyanthranilic Acid; D004926:Escherichia coli / Q000201:enzymology; D007700:Kinetics; D015394:Molecular Structure; D010084:Oxidation-Reduction; D013482:Superoxide Dismutase / Q000378:metabolism*; D062367:ortho-Aminobenzoates
D062367:ortho-Aminobenzoates; D015095:3-Hydroxyanthranilic Acid; D013482:Superoxide Dismutase