Electrophoresis

This is a method based on differences in protein movement speed in an electric field, depending on the solution’s pH – ionic strength. Their movement speed is proportional to the total charge of proteins. Proteins with a common negative charge move towards the anode (+), while those with a positive charge move towards the cathode (-). Electrophoresis is performed using various carriers: paper, membrane, starch gel, polyacrylamide gel, agar, etc. Unlike paper electrophoresis, where the speed of protein movement is proportional only to their total charge, in polyacrylamide gel, the speed of protein movement is proportional to their molecular weight. The resolving power in polyacrylamide gel is higher than in paper. To determine protein fractions, paper or gel strips are stained. The most commonly used stains are bromophenol blue, amido black 10B, etc. The intensity of staining, and therefore the relative amount of each protein fraction, is determined by densitometer.

Currently, protein electrophoresis methods are highly advanced: there is gel electrophoresis, immunoelectrophoresis, pulsed field electrophoresis, capillary electrophoresis, etc.

Source | Glossary of Most Commonly Used Biomedical Terms and Concepts | Lithuanian University of Health Sciences | Academician Professor Antanas Praškevičius, Professor Laima Ivanovienė