AbstractElectrophoresis is used to separate complex mixtures of proteins, (e.g., from cells, subcellular fractions, column fractions, or immunoprecipitates) to investigate subunit compositions, and to verify homogeneity of protein samples. It can also serve to purify proteins for use in further applications. In polyacrylamide gel electrophoresis, proteins migrate in response to an electrical field through pores in the gel matrix; pore size decreases with higher acrylamide concentrations. The combination of gel pore size and protein charge, size, and shape determines the migration rate of the protein. This unit contains protocols for standard Laemmli gels, electrophoresis of peptides and small proteins, continuous SDS‐PAGE ultrathin gels, multiple single‐concentration gels, gradient gels, and multiple gradient gels.
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