The effect of cyst(e)ine on the auto-oxidation of homocysteine.
This study examines the effect of cysteine on the auto-oxidation of homocysteine, a process that has been implicated in the pathologic mechanism of hyperhomocystinemia with respect to arteriosclerosis and vascular disease. It is shown that homocysteine autoxidizes at a much slower rate than cysteine, but that low concentrations of cysteine or cystine dramatically accelerate homocysteine oxidation and increase the rate of homocysteine-dependent oxygen consumption. It is proposed that the major role of homocysteine is to reduce cystine to cysteine, and that cysteine autoxidation is the mechanism by which thiol-dependent oxidative stress occurs.
Hogg
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Biophysics Research Institute, Medical College of Wisconsin, Milwaukee 53226, USA. nhogg@mcw.edu
D003545:Cysteine / Q000737:chemistry*; D003553:Cystine / Q000737:chemistry*; D005978:Glutathione / Q000737:chemistry; D006710:Homocysteine / Q000737:chemistry*; D010084:Oxidation-Reduction
D006710:Homocysteine; D003553:Cystine; D005978:Glutathione; D003545:Cysteine