Spontaneous electrical potential oscillation on a filter impregnated with soybean lecithin placed between identical solutions of alanine

Filters impregnated with soybean lecithin, placed between two identical aqu eous alanine solutions, display spontaneous electric potential oscillations . Alanine solutions used in a large concentration range from 1 mM to 1 M pr oduce damped oscillatory behaviour with an exponential decay in time. The d ependence of decay time on concentration shows saturation behaviour which i s well fitted with a sigmoidal curve. Power spectra obtained by Fourier tra nsform show peaks specific for each concentration. When fitted with a Loren tzian curve in the peak domain, the centre of the peak height and width at half height could be extracted. All these parameters depend on alanine conc entration in a saturating pattern. (C) 2000 Elsevier Science B.V. All right s reserved.