What causes the cathodal movement of γ globulins at pH 8.6?

The movement of γ globulins towards the cathode at pH 8.6 can be attributed to electroendosmosis. At this pH, γ globulins carry a net negative charge, which would typically cause them to migrate towards the anode in an electric field. However, the phenomenon of electroendosmosis involves the movement of the surrounding liquid towards the cathode, carrying the negatively charged proteins along with it. This effect can enhance the cathodal migration of γ globulins, making it a key factor in their observed movement during electrophoresis.

In this context, while other options suggest mechanisms that could influence sample behavior during electrophoresis, they do not directly cause the cathodal migration of γ globulins at this pH. Thus, the fundamental principle at play in this scenario is the combination of the charge on the proteins and the electroendosmotic flow of the liquid.