Determining Molecular Weights of Proteins by SDS-PAGE
Run a gel with standard proteins of known molecular weights along with the polypeptide to be characterized
A linear relationship exists between the log10 of the molecular weight of a polypeptide and its Rf
Rf = ratio of the distance migrated by the molecule to that migrated by a marker dye-front
The Rf of the polypeptide to be characterized is determined in the same way, and the log10 of its molecular weight is read directly from the standard curve