ABSTRACT
Principles of protein electrophoresis 15 Electrophoresis on agarose 17 Electrophoresis on cellulosic media 19
Capillary zone electrophoresis 20 Densitometric scanning 26 References 29
When proteins migrate in an electrical field, the extent of their migration and the degree of the resolution of each band depend on several factors. Two key factors that affect the migration of any protein are its pI (see Chapter 1) and the pH of the buffer. The pI of any given protein is constant and dependent on its amino acid and carbohydrate content. However, the charge that the protein expresses is determined by the pH of the solution in which it is dissolved. For example, a protein such as fibrinogen has a pI of 5.5. In an electrophoresis buffer with a pH of 8.6, it donates protons to the buffer and is left with a net negative charge. However, in a solution with a pH of 4.0, it would accept a proton and has a net positive charge.
