Activation of Na+ and K+ pumping modes of (Na,K)-ATPase by an oscillating electric field.

摘要: Serpersu and Tsong (Sepersu, E. H., Tsong, T. Y. (1983) J. Membr. Biol. 74, 191-201; (1984) Chem. 259, 7155-7162) reported activation of a K+ pumping mode (Na,K)-ATPase by an oscillating electric field (20 V/cm, 1.0 kHz). Their attempts to activate Na+ at the same frequency were unsuccessful. We report here with strength as used previously V/cm) but much higher (1.0 MHz). At 3.5 degrees C optimal amplitude frequency, field-induced, ouabain-sensitive (0.2 mM ouabain incubated for 30 min) Rb+ influx ranged between 10 20 amol/red blood cell/h, corresponding efflux 15 varying source erythrocytes. No nor was stimulated applied in range 1 Hz MHz. These results indicate that only those transport modes require ATP splitting under physiological condition affected fields, although field-stimulated did not depend on cellular concentration 5 800 microM. Computer simulation four-state enzyme electroconformationally coupled alternating (Tsong, Y., Astumian, R. D. (1986) Bioelectrochem. Bioenerg. 15, 457-476; (1990) Annu. Rev. Biophys. 19, 83-106) reproduced main features above results.