Membrane potential and short circuit current in artificial phospholipid membranes in the presence of agents uncoupling oxidative phosphorylation

V. S. Markin, V. F. Pastushenko, L. I. Krishtalik, Ye A. Liberman, V. P. Topaly

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Abstract

In the work we have developed the theory of electric phenomena in artificial bimolecular phospholipid membranes. The agents uncoupling oxidative phosphorylation present in the membrane are regarded as carries of ions which independently cannot penetrate across the membrane. The mechanism of transfer is as follows. At one boundary of the membrane the carrier links up with an ion from solution. The complex formed under the influence of the electric field and concentration gradient moves to the other boundary. Here the attached ion passes into solution and the released carrier returns to the first boundary. The whole cycle is repeated anew. The general formula is derived for the current across the membrane for arbitrary concentrations of the ion transmitted and the carrier itself at different sides of the membrane. From it we find the membrane potential set up on the membrane in absence of current. Its dependence on the concentration of the ion carried is analysed. It was found to be nonmonotonic: at certain concentrations in the pK region of the uncoupling agent a maximum of the membrane potential is reached. The result is compared with the experimental giving the same dependence. We have investigated a short-circuit current appearing on maintenance on both sides of the membrane of identical potentials. The current in this situation may be due only to the drop in the concentrations of the carried ion or the carrier itself. The results are also compared with the experimental. The current-voltage characteristic is examined. Its properties depend on the charge on the carrier. If the charge is such that either the carrier itself or the complex with the ion carried is neutral then the current-voltage curve is monotonie. For other charges when both forms are charged, a diminishing zone may appear in the currentvoltage curve.

Original languageEnglish (US)
Pages (from-to)487-500
Number of pages14
JournalBiophysics
Volume14
Issue number3
StatePublished - Dec 1 1969

ASJC Scopus subject areas

  • Biophysics

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    Markin, V. S., Pastushenko, V. F., Krishtalik, L. I., Liberman, Y. A., & Topaly, V. P. (1969). Membrane potential and short circuit current in artificial phospholipid membranes in the presence of agents uncoupling oxidative phosphorylation. Biophysics, 14(3), 487-500.