title: Inhibition of the thiol-specific antioxidant activity of rat liver MSP23 protein by hemin.
abstract: Mouse stress-inducible 23-kDa protein (MSP23) belongs to a new type of antioxidative protein family and is highly expressed in livers. To examine its physiological role in the tissue, we have purified native MSP23 protein from the cytosolic fraction of rat liver. The purified protein showed the thiol-specific antioxidant activity and protected glutamine synthetase from inactivation by a mixed metal-thiol oxidation. We examined the effect of hemin on that activity since it was recently shown by others that the rat liver MSP23 protein had a high binding affinity to heme. We have found that hemin at low concentrations inhibits the antioxidative activity of MSP23. This result suggests that one type of oxidant damage caused by hemin to cells is due to inactivation of the antioxidative protein, MSP23.
mesh_terms: D000645:Ammonium Sulfate; D000818:Animals; D000975:Antioxidants; D055598:Chemical Phenomena; D011232:Chemical Precipitation; D002627:Chemistry, Physical; D003600:Cytosol / Q000737:chemistry; D004229:Dithiothreitol / Q000494:pharmacology; D005974:Glutamate-Ammonia Ligase / Q000037:antagonists & inhibitors; D006360:Heat-Shock Proteins / Q000037:antagonists & inhibitors*; D006427:Hemin / Q000494:pharmacology*; D008099:Liver / Q000737:chemistry*; D008623:Mercaptoethanol / Q000494:pharmacology; D010084:Oxidation-Reduction; D010544:Peroxidases; D054464:Peroxiredoxins; D051381:Rats; D017207:Rats, Sprague-Dawley; D013438:Sulfhydryl Compounds / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D006360:Heat-Shock Proteins; D013438:Sulfhydryl Compounds; D008623:Mercaptoethanol; D006427:Hemin; D010544:Peroxidases; C489898:Prdx1 protein, rat; D054464:Peroxiredoxins; C489899:Prdx1 protein, mouse; D005974:Glutamate-Ammonia Ligase; D000645:Ammonium Sulfate; D004229:Dithiothreitol