Isoelectric focussing methods

Sugano M, Hidaka H, Yamauchi K, Nakabayashi T, Higuchic Y, Fujita K, et al. Analysis of hemoglobin and globin chain variants by a commonly used capillary isoelectric focussing method. Electrophoresis 2000 21 3016-9. 

SDS-PAGE was performed by the method of Laemmli [17]. The methods for native PAGE, isoelectric focussing, detection of esterase activity in electrophoresis gels, and assays for protein glycosylation have been described elsewhere [5]. 

A much better technique of protein purification is that of isoelectric focussing. Use is made of the isoelectric point of a protein. Suppose that the isoelectric point of a protein is 6.0. If we prepare a pH gradient in a column so that the pH varies from 1-10 and place all the proteins in the sample on top of the column and start the current, all the proteins will migrate dependent on the charge that they possess. At the space where pH of the gradient is 6, while other proteins will continue moving, the desired protein will become immobile since it possesses no net charge the pH is isoelectric for it. The method is discussed in reasonable details in Chapter 12. 

This technique was discovered by H. Svensson in Sweden and has a high-resolution powra. A simple comparison would help establish the method s supremacy over other methods while paper electrophoresis resolves plasma proteins into six bands, isoelectric focussing resolves It into atleast 40 bands. 

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