There is no good simple theory to describe mobility of proteins or nucleic acids in gels. However, experiment is quily developed, using empirical approach. From this simple equation we can predict that velocity of the molecule will decrease with increase if ionic strength due to contra-ion shielding and consecutive decrease of its net charge. Another simple explanation is that ions present in the buffer counterbalance applied electric field, making it weaker, therefore mobility of charged molecule is decreased. A set of proteins migrate as a whole in the electric field.
All separation is based on their interaction with the gel.
I 2 R. Increase in current will heat up the gel. Alternatively, if thickness of gel is decreased, then R will decrease as well, and voltage can be further increased at the same amount of produced heat. Electroosmosis Since we deal with 55 M water solution, mostly effects on electrodes are due to electrolysis of water. This effect is called electroosmosis. It can be used to eluted proteins from the gel.