Mechanismus und Selektivität des Alkali‐Ionentransportes in Modell‐Membranen in Gegenwart des Antibioticums Valinomycin

Abstract Selective transport of potassium ions through synthetic membranes impregnated with valinomycin in octane‐2‐ol in the presence of equal amounts of K+ and Na+ or Li+ ions is induced on application of a potential difference across these membranes. By using 14C‐labelled valinomycin it is shown that transport of potassium ions is accompanied by an equivalent transport of valinomycin within the membrane, consistent with the formation of a 1 : 1 complex of K+ with valinomycin. The exchange of ligands is shown to occur during the transport process so that a carrier‐relay mechanism, as proposed earlier for macrotetrolide‐mediated potassium transport, accounts for all experimental results on the bulk membranes studied.