can be used pH= 7

Which antidote do you mean? Or do you mean "anode", the positive pole?

• Proteins move to the electrode with opposite charge, the charge of a protein is determined by pH. If the pH is lower than its pI, the protein will bind additional protons and hence have a positive net charge. If the pH is higher than pI, the protein will lose protons and have negative net charge. The latter is the situation you want if the protein should move towards the positive pole.
• In addition, you want to consider solubility of your protein, which is lowest in the uncharged state, i.e., at the pI. Therefore, you want to have a pH that is at least one unit away from the pI (either higher or lower, depending on the polarity of your electrophoretic system).
• Thirdly, you want the pH to be in a region where your protein is stable, especially if you want to do zymograms (detect an enzyme in the gel by its activity). Working near the pH of the natural environment of the protein is a quick and dirty way to ensure that. Do consider, however, that the pH surrounding the protein changes during discontinuous electrophoresis.

doi:10.1111/j.1749-6632.1973.tb47551.x is a systematic study on buffer systems for electrophoresis. doi:10.1006/abio.1994.1112 describes blue native page, a method where CBB is used as a non-denaturing alternative to SDS, doi:10.1110/ps.0233903 describes the use of perfluoroctan for this purpose. For zymograms cationic detergents like CTAB may also work (doi:10.1007/978-1-59745-542-8_14). I have described the theory of electrophoresis in doi:10.1007/978-1-4419-7251-4_8.