Protein electrophoresis


Electrophoresis is a method to separate different kinds of molecules (including DNA). Gel electrophoresis separates the different molecules in a mixture by letting them pass through a gel, driven by an electric current. The gel is placed in a tank with an ionic buffer, and the mixture to separate is injected onto the gel near the anode. When the electric current is applied, the (negatively charged) molecules travel towards the (positive) cathode. The smaller and the more negatively charged the molecules are, the faster they pass through the gel.

After the electrophoresis run, when the smallest molecules have almost reached the anode, the molecules in the gel can be stained to make them visible.

In chemistry and medicine, protein electrophoresis is a method of analysing a mixture of proteins by means of gel electrophoresis, mainly in blood serum (blood plasma is not suitable).


There are two large classes of blood proteins: albumin and globulin. They are generally equal in proportion, but albumin is much smaller and lightly negatively charged, leading to an accumulation of albumin on the electrophoretic gel. A small band before albumin represents transthyretin (also named pre-albumin). Some forms of medication or body chemicals can cause their own band, usually small (see, however, paraprotein).

The globulins are classified by their banding pattern (with their main representatives):

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