Ampholine-ampholine interaction as a couse of pH gradient drift in isoelectric focusing

Two mechanisms for the cathodic drift in isoelectric focusing are proposed: (1) Ampholine-Ampholine interaction between acidic and basic species, particularly in the pH range 6-7; the aggregates are slowly split during the focusing process, to an extent proportional to the square of the voltage applied; and (2) the presence of transient species of "poor" carrier ampholytes, particularly at allkaline pH. The resultant of these two "transient states" is to set in motion a "cascade" effect on the "steady-state" species, the net effect of which is a drift to the cathode. The markedly different behaviour of acidic and basic carrier ampholytes is demostrated via binding to a neutral detergent, Nonidet P40.