[Mechanism of histone action on mitochondrial energetics. Proton and cation transport across membrane].

The effect of lysine-rich histone on mitochondria was studied with respect to the cation transport and proton uptake across the membrane. Histone does not affect Ca2+ uptake or level in mitochondria. It extrudes Mg2+ by 30% with the utilization of substrates; in the presence of rotenone extrusion drops to about 18%. Dinitrophenol and ADP prevent the effect of histone. Mg2+ uptake is inhibited by 12% by histone. K+ extrusion by histone (by 50%) which depends on the oxidation of substrates, is enhanced by phosphate, and Mg2+ decreases (by 50%) the K+ extrusion. Histone prevents to some extent extrusion of K+ by Ca2+. Histone does not affect Na+ level in mitochondria, it blocks (by 50%) Na+ uptake in the presence of gramicidin, probably by forming a gramicidin-histone complex. Histone blocks proton uptake by mitochondria incubated in the presence of valinomycin or DNP. In the presence of DNP valinomycin-induced H+ uptake is not affected by histone. H+ uptake induced by nigericin is not affected by histone as well.