Activation of energy-linked K+ accumulation in isolated heart mitochondria by non-ionic detergents

Summary Sub-lytic concentrations of a non-ionic detergent such as Triton X-100 or Lubrol WX markedly activate energy-dependent ion accumulation and osmotic swelling of beef heart mitochondria suspended in media containing acetate or phosphate salts. Both the efficiency and the absolute amount of ion accumulation are increased by the detergent. The detergent-dependent increment in acetate or phosphate uptake is specific for K + and, like the spontaneous ion uptake reaction, is sensitive to and reversed by dinitrophenol and other uncouplers. These results suggest that mitochondrial ion accumulation is normally limited by the low permeability of the membrane to K + , and that in the presence of the detergent the membrane is altered so that this restriction is decreased.