Electrophoresis is a technique which separates charged substances according to differences of electric charge and molecular structure. When two substances having opposite charges are applied at different positions and electrophoresed they will cross each other during electrophoresis. When two substances have the same charge but different mobilities, the faster moving substance will overrun and migrate ahead of the slower one.
POLYACRYLAMIDE GEL ELECTROPHORESIS PAGDE: POLYACRYLAMIDE GEL DISC ELECTROHPRESIS