Gel electrophoresis is the most frequently used method for protein separation. The main principle of electrophoretic separation is to apply an electric field to force molecules to move through gel pores, separating them based on their molecular weight and total particle charge. In general, larger molecules migrate more slowly in the gel with a higher percent concentration than smaller ones.
The electrophoretic mobility of a protein is a complex function in gel electrophoresis, influenced by several factors: (1) the charge, size, and shape of the protein itself; (2) composition, pH value, ionic strength, viscosity, permittivity, and temperature of the background electrolyte in which protein moves; and (3) interactions between proteins and background electrolyte components, including solvation, dissociation, and complex formation.
Electrophoretic separation can be performed under different conditions, either to maintain protein complexes intact or to dissociate them to obtain and identify specific components. The desired results depend on the gel types, detergents, buffers, etc.
For the evaluation of molecular size of proteins in gels
For the visualization of proteins in gels and on membranes
For the separation of protein molecular mixtures