High-sensitivity silver staining of proteins following polyacrylamide gel electrophoresis.

Polyacrylamide gel electrophoresis is a simple, inexpensive, yet highly versatile and powerful method for the analysis of complex mixtures of proteins. In part, the success of this method has resulted from the ease with which the fractionated proteins can be detected with the blue dye, Coomassie brilliant blue R 250. However, though this stain has proved to be ideal for many of the more traditional applications of this method, it is of limited sensitivity. In particular, the recent development of two-dimensional gel electrophoresis ( Chapter 10 ) and in situ peptide mapping techniques ( Chapter 22 ) have demanded increasingly more sensitive detection methods. In part, this requirement has been met by the use of radioactively labeled proteins, followed by either autoradiography or fluorography ( Chapter 9 ). The principal drawback of this approach is that it involves additional sample preparation and it is often difficult to label the proteins to a sufficiently high specific activity, particularly where proteins are obtained from dilute physiological samples, and so on.