Recovery of protein by Coomassie Brilliant Blue precipitation prior to electrophoresis

The interaction of protein with Coomassie Brilliant Blue G-250 results in formation of an insoluble protein-dye complex which can be recovered by centrifugation and redissolved for electrophoretic analysis. The precipitated protein can be washed in acetone to remove excess dye in order to enhance resolution. The residual dye becomes dissociated from the proteins on electrophoresis and can be exploited as a "dye front". The method allows simultaneous protein assay and recovery of microgram amounts of protein from dilute solution and could be widely applied for conserving, concentrating and desalting minute amounts of valuable sample prior to electrophoretic analysis.