Measuring Molecular Weight with SDS-PAGE

The mobility (Rf) of a molecule in gel electrophoresis is determined by its free solution mobility, Y0 (= mobility in a gel of zero %) and the sieving action of the gel matrix. In denaturing protein electrophoresis, the addition of SDS to the electrophoresis buffer uniformly coats the proteins with negative charges, equalizing the charge…

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Denaturing Protein Electrophoresis: SDS-PAGE

In their native form, proteins fold into a variety of shapes, some compact, some elongated. The rate of migration of native proteins through a sieving medium is therefore more a reflection of their relative compactness, and less an accurate measure of molecular weight. Denaturing the proteins nullifies structural effects on mobility, allowing separation on a…

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