The silver staining procedure of sodium dodecyl sulfate-gels may be accelerated by shortening fixation time

In most silver staining methods the first step in the staining of proteins separated after sodium dodecyl sulfate-polyacrylamide gel electrophoresis is a rather protracted fixation of the gels. Optimum fixation should be short, cause no background staining and effectively immobilize the proteins in the gel without masking the proteins for reaction with the staining solution. Further, the concentration of the fixing compounds should be as low as possible due to the potential toxicity of fixatives. Fixation for only 5 min with mixtures of very low concentrations of formaldehyde and glutaraldehyde in ethanol, or a solution of formaldehyde or glutaraldehyde in picric acid and ethanol, fulfill these demands, provided that the gels were prefixed in ethanol-acetic acid for 10 min. As a consequence of these results a fast and sensitive silver staining procedure is proposed.