Inhibition of metal-catalyzed oxidation systems by a yeast protector protein in the presence of thiol.
A protector protein from Saccharomyces cerevisiae prevented the inactivation of enzyme and oxidative damage to protein and DNA caused by a thiol/Fe3+/O2 metal-catalyzed oxidation (MCO) system but not when thiol was replaced by ascorbate. In the presence of a reduced thiol such as dithiothreitol and reduced glutathione, however, the protector protein prevented inactivation of E. coli glutamine synthetase against a MCO system comprised of ascorbate and Fe3+. The protector protein also inhibited the fragmentation of protein, incorporation of carbonyl groups into protein, strand breaks in pBluescript plasmid DNA, and the formation of 8-hydroxydeoxyguanosine in calf thymus DNA when induced by either the thiol/Fe3+ system or the ascorbate/Fe3+ system supplemented with dithiothreitol. These results suggest that antioxidant activity of protector protein against a MCO system requires thiol as a reducing equivalent to restore its catalytic activity.
Kwon
S J
SJ
Department of Food and Nutrition, Chonnam National University, Kwangju, Korea.
Park
J W
JW
Kim
K
K
D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology; D004249:DNA Damage; D004229:Dithiothreitol / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology; D005290:Ferric Compounds / Q000494:pharmacology; D005656:Fungal Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D005974:Glutamate-Ammonia Ligase / Q000037:antagonists & inhibitors*; D005978:Glutathione / Q000031:analogs & derivatives / Q000494:pharmacology; D019803:Glutathione Disulfide; D007501:Iron / Q000494:pharmacology*; D007700:Kinetics; D009363:Neoplasm Proteins; D010084:Oxidation-Reduction; D010100:Oxygen / Q000494:pharmacology; D010544:Peroxidases; D054464:Peroxiredoxins; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D013438:Sulfhydryl Compounds / Q000494:pharmacology*
D000975:Antioxidants; D005290:Ferric Compounds; D005656:Fungal Proteins; D009363:Neoplasm Proteins; D013438:Sulfhydryl Compounds; C061126:iron(III)-ascorbic acid complex; D007501:Iron; D010544:Peroxidases; D054464:Peroxiredoxins; D005974:Glutamate-Ammonia Ligase; D005978:Glutathione; D001205:Ascorbic Acid; D010100:Oxygen; D004229:Dithiothreitol; D019803:Glutathione Disulfide