Protein Chemistry. Structure, Properties, Research Methods - Shendryk A.N. 2022

Methods for Experimental Study of Protein Structure
Protein Separation Methods
Experimental Methods of Electrophoresis - Frontal Electrophoresis

The frontal Electrophoresis method (also known as the moving boundary method) was developed by Tiselius, who designed a special Cell for this purpose. The Essence of the method is as follows. A protein solution is placed in a U-shaped transparent cell. Pure buffer is then carefully layered on top of the solution. Afterward, an electric field is applied to the system at a constant Temperature and under vibration-free conditions.

When the protein moves from the solution into the pure buffer zone under the Influence of the field, a boundary is created that moves toward one of the electrodes (depending on the charge of the protein molecule). A sharp change in the refractive index is observed at this boundary, which is due to the difference in the refractive indices of the pure buffer and the protein solution in the buffer. Based on measurements of the refractive index gradient along The Cell using a special optical technique known as the schlieren method, an electrophoregram is constructed (see fig.)

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Each peak on the electrophoregram corresponds to THE POSITION OF the moving boundary of a specific protein. It does not coincide with the maximum protein concentration.

Recently, the Tiselius electrophoresis variant has practically ceased to be used, having been replaced by more advanced and convenient techniques.