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Type: Artigo de periódico
Title: Membrane Protein Thiol Cross-linking Associated With The Permeabilization Of The Inner Mitochondrial Membrane By Ca2+ Plus Prooxidants.
Author: Fagian, M M
Pereira-da-Silva, L
Martins, I S
Vercesi, A E
Abstract: In a previous report (Macedo, D.V., Ferraz, V. L., Pereira-da-Silva, L., and Vercesi, A. E. (1988) in Integration of Mitochondrial Functions (Lemasters, J. J., et al., eds) pp. 535-542, Plenum Publishing Corp., New York), we proposed that the alterations in the inner mitochondrial membrane permeability caused by Ca2+ plus prooxidants could be the consequence of membrane protein sulfhydryl-disulfide transitions. In this study, we show that Ca2+ plus diamide, a thiol oxidant, significantly decrease the ability of beef heart submitochondrial particles to build up and sustain a membrane potential generated by succinate oxidation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of solubilized membrane proteins indicates that these effects on the membrane potential are associated with the production of protein aggregates due to thiol cross-linking. Evidence is also presented that these protein aggregates can be produced in mitoplasts previously loaded with Ca2+ and that this is potentiated by the presence of either diamide or t-butylhydroperoxide. Furthermore, dithiothreitol, a disulfide reductant, was found to be much more effective than NAD(P)+ reductants in reversing Ca2+ efflux induced by prooxidants. It is concluded that the perturbation of the inner mitochondrial membrane caused by Ca2+ plus prooxidants is associated with protein polymerization due to thiol cross-linking, resulting in the production of high molecular mass protein aggregates.
Subject: Animals
Cell Membrane Permeability
Egtazic Acid
Electrophoresis, Polyacrylamide Gel
Intracellular Membranes
Membrane Potentials
Membrane Proteins
Mitochondria, Heart
Mitochondria, Liver
Submitochondrial Particles
Succinic Acid
Sulfhydryl Compounds
Citation: The Journal Of Biological Chemistry. v. 265, n. 32, p. 19955-60, 1990-Nov.
Rights: fechado
Date Issue: 1990
Appears in Collections:Unicamp - Artigos e Outros Documentos

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