Effect of sodium and potassium ions on mitochondrial oxidative phosphorylation. Studies with arsenate
Por:
Sandoval F., Gómez-Puyou A., Tuena M., Chávez E., Peña A.
Publicada:
1 ene 1970
Resumen:
The effect of arsenate on the oxidative phosphorylation process has been studied in rat liver mitochondria incubated in media which contain ethylenediaminetetraacetate and either Na+ or K+. It was found that arsenate stimulated adenosine triphosphatase activity more effectively in mitochondria incubated in the sodium medium than in the potassium medium and that the activation of oxygen uptake by arsenate is less in mitochondria incubated with Na+ than with K+. The 32P-adenosine triphosphate exchange reaction and its inhibition by arsenate are not affected differently by Na+ or K+. The rate of respiration of mitochondria incubated with K+ and arsenate is increased by adenosine diphosphate and inhibited by inorganic phosphate, whereas the oxygen uptake of mitochondria incubated with Na+ is not ostensibly affected by either adenosine diphosphate or inorganic phosphate. The respiration of mitochondria treated with arsenate and phosphate is stimulated by adenosine diphosphate and 2,4-dinitrophenol in the presence of K+, but not Na+. On the other hand, adenosine diphosphate inhibits the arsenate stimulated adenosinetriphosphatase activity in the sodium medium more effectively than in the potassium medium. These findings suggest that Na+ and ethylenediaminetetraacetate induce in mitochondria an alteration which precludes the participation of Pi in mitochondrial oxidative phosphorylation.
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