Oxidative stress causes intracellular reversible S-thiolation of chicken hemoglobin under diamide and xanthine oxidase treatment.
Time courses of total (GSH-t), disulfide (GSSG), and mixed disulfide (PSSG) forms of glutathione were studied in chicken blood submitted to oxidative stress induced by diamide or by the reactive oxygen species (ROS)-producing system xanthine/xanthine oxidase (X/XO). Diamide-treated blood induced an immediate increase in GSSG and PSSG, while X/XO produced a slow and sustained stress with increased values of GSSG and PSSG only after 30 and/or 60 min of incubation. Both total protein S-thiolation (mixed disulfide with glutathione) and dethiolation and hemoglobin A S-thiolation and dethiolation were clearly observed. Hemoglobin A (Hb A) was the major S-thiolated protein. We further characterized chicken Hb S-thiolation through the reaction of Hb with GSSG or the GSH/GSSG redox couple. Methemoglobin levels did not change with diamide or with X/XO treatment. Present results suggest that the most reactive cysteine pair of Hb A, the major chicken Hb, might function as an antioxidant under in vivo oxidative stress conditions.
Curso de Pós-Graduação em Fisiologia e Departamento de Biofísica, Universidade Federal do Rio Grande do Sul, Ave. Sarmento Leite, 500, Porto Alegre-RS, 90050-170, Brazil. aldafre@ufsc.br
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Dafré
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Reischl
D000818:Animals; D002645:Chickens; D003958:Diamide / Q000494:pharmacology*; D004912:Erythrocytes / Q000378:metabolism; D005978:Glutathione / Q000097:blood; D019803:Glutathione Disulfide / Q000097:blood; D006441:Hemoglobin A / Q000737:chemistry / Q000378:metabolism*; D007424:Intracellular Fluid / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D018384:Oxidative Stress; D013438:Sulfhydryl Compounds / Q000097:blood*; D014969:Xanthine Oxidase / Q000494:pharmacology*
D013438:Sulfhydryl Compounds; D003958:Diamide; D006441:Hemoglobin A; D014969:Xanthine Oxidase; D005978:Glutathione; D019803:Glutathione Disulfide