title: Hemoglobin S-thiolation during peroxide-induced oxidative stress in chicken blood.
abstract: 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.
authors.affiliation: Departamento de Ciências Fisiológicas, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil. Electronic address: aldafre@ccb.ufsc.br.
authors.forename: Alcir Luiz
authors.initials: AL
authors.lastname: Dafre
authors.affiliation: Departamento de Ciências Fisiológicas, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil. Electronic address: reisev@yahoo.com.
authors.forename: Evaldo
authors.initials: E
authors.lastname: Reischl
mesh_terms: 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*
chemical_list: D000975:Antioxidants; D001555:Benzene Derivatives; D004220:Disulfides; D006454:Hemoglobins; D013438:Sulfhydryl Compounds; C015763:cumene; D020122:tert-Butylhydroperoxide; D006861:Hydrogen Peroxide; D005978:Glutathione