[Physicochemical mechanisms of the action of gramicidin S on a model membrane]

Influence of gramicidin S on electric parameters of nitrocellulose ultrafilter as a biomembrane model was studied, the ultrafilters being impregnated with fatty acids or their ethers. It was shown that addition of the antibiotic to the solution over one side of the model membrane resulted in generation of electric potential. With increasing of the drug concentration by one order there was observed more than a 10-fold drop in the membrane resistance while the electric capacitance actually remained unchanged. It was suggested that gramicidin S was localized in thin water layers covering the surface of the ultrafilter pores and separating the polymer matrix and impregnating liquid filling the pores. Such incorporation led to changes in the state of water and water channel surfaces which defined the increase in the model membrane electric conductivity.