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|Type:||Artigo de periódico|
|Title:||Permeabilization Of The Inner Mitochondrial Membrane By Ca2+ Ions Is Stimulated By T-butyl Hydroperoxide And Mediated By Reactive Oxygen Species Generated By Mitochondria|
|Abstract:||The extent of swelling undergone by deenergized mitochondria incubated in KC1/sucrose medium in the presence of Ca2+ alone or Ca2+ and t-butyl hydroperoxide decreases by decreasing molecular oxygen concentration in the reaction medium; under anaerobiosis no swelling occurs. This swelling is also inhibited by the presence of exogenous catalase or by the Fe2+ chelator o-phenanthroline in a time-dependent manner. The production of protein thiol cross-linking that leads to the formation of protein aggregates induced by Ca2+ and t-butyl hydroperoxide does not occur when mitochondria are incubated in anaerobic medium or in the presence of o-phenanthroline. In addition, it is also shown that the yield of stable methyl radical adducts, obtained from rat liver mitochondria treated with t-butyl hydroperoxide and the spin trap DMPO, is reduced by addition of EGTA and increases by addition of Ca2+ ions. These data support the hypothesis that Ca2+ ions stimulate electron leakage from the respiratory chain, increasing the mitochondrial production of reactive oxygen species. © 1995.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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