Peroxynitrite oxidizes erythrocyte membrane band 3 protein and diminishes its anion transport capacity |
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| Authors: | Gloria Celedón José Pino Eduardo A Lissi |
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| Institution: | 1. Departamento de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile;2. Facultad de Ciencias Básicas y Matemáticas, Instituto de Química, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile;3. Facultad de Biología y Química, Universidad de Santiago de Chile, Santiago, Chile |
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| Abstract: | We describe an altered membrane band 3 protein-mediated anion transport in erythrocytes exposed to peroxynitrite, and relate the loss of anion transport to cell damage and to band 3 oxidative modifications. We found that peroxynitrite down-regulate anion transport in a dose dependent relation (100–300 μmoles/l). Hemoglobin oxidation was found at all peroxynitrite concentrations studied. A dose-dependent band 3 protein crosslinking and tyrosine nitration were also observed. Band 3 protein modifications were concomitant with a decrease in transport activity. ( ? )-Epicatechin avoids band 3 protein nitration but barely affects its transport capacity, suggesting that both processes are unrelated. N-acetyl cysteine partially reverted the loss of band 3 transport capacity. It is concluded that peroxynitrite promotes a decrease in anion transport that is partially due to the reversible oxidation of band 3 cysteine residues. Additionally, band 3 tyrosine nitration seems not to be relevant for the loss of its anion transport capacity. |
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| Keywords: | Erythrocyte peroxynitrite anion transport band 3 |
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