Electrophoretic migration velocity of amphiphilic proteins increases with decreasing Triton X-100 concentration: A new characteristic for their identification

Abstract

The relation between the electrophoretic migration velocity and the concentration of the non-ionic detergent Triton X-100 in the buffer was studied by crossed immunoelectrophoresis of hydrophilic and amphiphilic proteins. The migration velocity of hydrophilic human plasma proteins was not affected by the presence of Triton X-100 in the agarose gels in the concentration range of 1–0 % v/v. In contrast, amphiphilic proteins, like the human erythrocyte proteins glycophorin, band 3 protein and acetylcholinesterase, and the plasma high density lipoprotein (HDL) apolipoprotein, showed increasing migration velocity with decreasing detergent concentration in the gels. An increase of 20–80 % was observed for different amphiphilic proteins when the Triton X-100 concentration was lowered from 1 % to 0.03 % v/v. This probably reflects the influence of the size of the bound detergent micelle on the charge density of the protein. Thus, by performing corssed immunoelectrophoresis with different concentrations of Triton X-100 in the first-dimensional gel it is possible to identify amphiphilic proteins. Presence of 1 % v/v Triton X-100 in the second-dimensional gel ensures reliable identification of the precipitates.