Zero-current membrane potentials (Vm) of diphytanoyl phosphatidylcholine/n-decane membranes in the presence of DipA measured for a five-fold concentration gradient of different electrolytes.

Vm is defined as the difference between the potential at the dilute side (100 mM) and the potential at the concentrated side (500 mM). The aqueous electrolyte solutions were buffered with 10 mM Tris-HCl (pH 7.5); temperature = 20°C; The permeability ratio Pc/Pa was calculated using the Goldman-Hodgin-Katz equation [62] from at least three individual experiments.