COMBINATION OF THE ELECTROGENIC IONOPHORES, VALINOMYCIN AND CCCP, CANLEAD TO NON-ELECTROGENIC K+ H+ EXCHANGE ON BILAYER-LIPID MEMBRANES/

The method of pH shift measuring by means of a pH microelectrode was a pplied to measure hydrogen ion fluxes across a planar bilayer lipid me mbrane (BLM) in the presence of the potassium ion ionophore, valinomyc in, and a protonophore, carbonylcyanide m-chlorophenylhydrazone (CCCP) , under conditions of the voltage clamp. The voltage dependence of the flux was determined to be in the range of +/-150 mV under the conditi ons of both symmetrical KCl as well as a KCl gradient across the BLM. Surprisingly, at a clamped zero voltage on BLM a significant hydrogen ion flux was observed in the presence of a KCL gradient and both valin omycin and CCCP, This finding was interpreted as a result of induction of non-electrogenic K+/H+ exchange in the presence of valinomycin and CCCP, presumably through the formation of electrically neutral comple xes of these two ionophores and K+ (H+) ions: valinomycin-K+-CCCP- and /or possibly valinomycin-CCCP--H+.