Figure 5.9 The staining of proteins after electrophoresis. Proteins subjected to electrophoresis on an SDS–polyacrylamide gel can be visualized by staining with coomassie blue. The lane on the left is a set of marker proteins of known molecular weight. These marker proteins have been separated on the basis of size, with the smaller proteins moving farther into the gel than the larger proteins. Two different protein mixtures are in the remaining lanes.