In zone electrophoresis, serum proteins have been fractionated on the basis of their electrical charge into five classical fractions: albumin, alpha1, alpha2, beta, and gamma proteins.
Each of these classical electrophoretic zones (with the exception of albumin) normally contains two or more components. Approximately fifteen serum proteins have been studied extensively because they may be measured easily.
PRINCIPLE OF METHOD
Proteins are large molecules composed of covalently linked amino acids. Depending on electron distributions resulting from covalent or ionic bonding of structural subgroups, proteins have different electrical charges at a given pH.
In this procedure, the proteins are separated according to their respective electrical charges at pH 8.8 on a cellulose acetate membrane using both the electrophoretic and electroendosmotic forces present in the system.
After the proteins are separated, the membrane is placed in a solution of Trichlorineaceti acid and Ponceau S (to stain the protein bands). Destaining solution, permits the appreciation of the 5 proteic fractions: albumin, alpha1, alpha2, beta, and gamma proteins.
The following densitometric scanning, allows the graphical rapresentation of Electrophoresis separation curve, and the calculation of the percent value of each single fraction. The staining intensity is related to protein concentration.