SDS‐Polyacrylamide Gel Electrophoresis (SDS‐PAGE) of Proteins

Abstract Electrophoresis is a method by which a complex mixture of proteins can be separated. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE) is a technique used to move charged molecules through a gel matrix by means of an electric current. This procedure is used to determine protein subunit composition, verify homogeneity of the protein sample, and purify proteins for use in other applications. The migration rate of the proteins during SDS‐PAGE is determined by the pore size of the gel matrix and charge, size, and shape of the protein. In this unit, the protocol covers the casting of gels, preparation of the protein samples, staining and drying of the gels, and calculation of molecular mass of the proteins based on electrophoretic mobility. Curr. Protoc. Microbiol . 22:A.3M.1‐A.3M.13. © 2011 by John Wiley & Sons, Inc.