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

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.