A gated pathway for electrophoretic Na+ fluxes in rat liver mitochondria. Regulation by surface Mg2+.

摘要: Addition of EDTA to mitochondria incubated aerobically in a phosphate-supplemented medium containing Na+ ions results activation cation uptake which is accompanied by membrane depolarization and stimulation respiration. The same are obtained media Li+ but not K+, indicating that this pathway for transport selective. changes matrix Mg2+, controlled surface-bound rather than intramitochondrial respiring competitvely inhibited Mg2+ with Ki the nanomolar range. A current can also be induced K+ diffusion potential absence K+-diffusion-driven has magnitude or presence inorganic phosphate, suggesting mediated uniport electrogenic nNa+/H+ antiport n > 1. Analysis flow/force relationship indicates putative uniporter conductance about 0.2 nmol Na+× mg protein−1× min−1× mV−1, it active only when exceeds 150 mV.