One-dimensional SDS gel electrophoresis of proteins.

Electrophoresis is used to separate complex mixtures of proteins, 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 that gives the standard Laemmli method for discontinuous gel electrophoresis under denaturing conditions, and the standard method for full-size gels is adapted for the minigel format. Minigels provide rapid separation but give lower resolution. Several alternate protocols are provided for specific applications, including electrophoresis of peptides and small proteins, continuous SDS-PAGE, ultrathin gels, multiple single-concentration gels, gradient gels, multiple gradient gels, and multiple gradient minigels.