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Combination of the electrogenic ionophores, valinomycin and CCCP, can lead to non‐electrogenic K + /H + exchange on bilayer lipid membranes
Author(s) -
Orlov Victor N.,
Antonenko Yuri N.,
Bulychev Alexander A.,
Yaguzhinsky Lev S.
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)00420-x
Subject(s) - valinomycin , protonophore , chemistry , ionophore , analytical chemistry (journal) , membrane , bilayer , ion , ion transporter , inorganic chemistry , lipid bilayer , membrane potential , chromatography , biochemistry , organic chemistry
The method of pH shift measuring by means of a pH microelectrode was applied to measure hydrogen ion fluxes across a planar bilayer lipid membrane (BLM) in the presence of the potassium ion ionophore, valinomycin, 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 conditions 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 valinomycin 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 complexes of these two ionophores and K + (H + ) ions: valinomycin—K + —CCCP − and/or possibly valinomycin—CCCP − —H + .