Hemoglobin S-thiolation during peroxide-induced oxidative stress in chicken blood.
Protein S-thiolation or protein-glutathione mixed disulfide (PSSG) occurs when cells are exposed to oxidative stress, and has been implicated in several cellular functions. The S-thiolation of hemoglobin as well as other abundant proteins is proposed to participate as a redox buffer, being part of the antioxidant protection system of the cell during the oxidative challenge. We studied the oxidative stress caused by peroxides (H(2)O(2), cumene and tert-butyl hydroperoxide) on chicken blood by measuring the thiol/disulfide status. Chicken blood under peroxide treatment showed a time- and concentration-dependent increase in glutathione disulfide (GSSG) and PSSG. GSSG peaked immediately after treatment (1 min), while PSSG increased progressively over time, showing a maximum after about 30 min. The system recovered after 140 min of incubation, with GSSG and PSSG then barely reaching control values. The S-thiolation of hemoglobin was monitored under nondenaturing PAGE, and the fraction of S-thiolated hemoglobin, or Hb A1, rose in a dose-dependent fashion and was proportional to total S-thiolation, measured as PSSG. This significant correlation indicates that hemoglobin is the major S-thiolated protein in chicken erythrocytes treated with peroxides. The present work shows the behavior of chicken blood under peroxide treatment; it anticipated that chicken hemoglobin thiol groups can actively participate in the redox processes of erythrocytes exposed to oxidative stress, and that hemoglobin is the major S-thiolated protein. This further corroborates the hypothesis that abundant proteins, such as hemoglobin, may take part in the cellular antioxidant defense system.
Dafre
Alcir Luiz
AL
Departamento de Ciências Fisiológicas, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil. Electronic address: aldafre@ccb.ufsc.br.
Reischl
Evaldo
E
Departamento de Ciências Fisiológicas, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil. Electronic address: reisev@yahoo.com.
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001555:Benzene Derivatives / Q000494:pharmacology*; D002645:Chickens / Q000097:blood*; D004220:Disulfides / Q000097:blood; D005978:Glutathione / Q000097:blood; D006454:Hemoglobins / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D066298:In Vitro Techniques; D018384:Oxidative Stress; D013438:Sulfhydryl Compounds / Q000097:blood*; D020122:tert-Butylhydroperoxide / Q000494:pharmacology*
D000975:Antioxidants; D001555:Benzene Derivatives; D004220:Disulfides; D006454:Hemoglobins; D013438:Sulfhydryl Compounds; C015763:cumene; D020122:tert-Butylhydroperoxide; D006861:Hydrogen Peroxide; D005978:Glutathione