Charge pulse studies of transport phenomena in bilayer membranes

Abstract

The charge-pulse technique is applied to a study of valinomycin-mediated potassium transport across glycerol monooleate (GMO) bilayers. The theory, based on the Läuger-Stark model, is developed for the steady-state domain. The voltage dependences of the surface complexation reactions are also considered. The analysis of the data yields the folowing values for the rate constants: (see article). With the exception of this last ratio, all the values agree well with previously published data. The implication of the exponential term, 0.045, is that the plane of reaction for the surface complexation actually occurs a small distance within the membrane dielectric. If one presumes that the reaction plane is about half way between the plane of adsorbed complex and the membrane-water interface, one deduces that the complex "feels" only about 80% of the applied voltage across the membrane.

An extended kinetic analysis of valinomycin-induced Rb-transport through monoglyceride membranes

“…Such an analysis, however, will inevitably require a higher degree of mathematical effort and also additional experimental information about the transport system. This information may be obtained by using different relaxation methods, such as the charge pulse method (Feldberg & Kissel, 1975) or the temperature jump method (Knoll & Stark, in preparation). Besides, the analysis outlined in this paper may now be applied to other lipids, such as phospholipids and other carrier molecules, for which the resolution of the faster relaxation process has recently been possible, too.…”