Improved staining of proteins in polyacrylamide gels including isoelectric focusing gels with clear background at nanogram sensitivity using Coomassie Brilliant Blue G‐250 and R‐250

Abstract An improved procedure for staining of proteins following separation in polyacrylamide gels is described which utilizes the colloidal properties of Coomassie Brilliant Blue G‐250 and R‐250. The new method is based on addition of 20 % v/v methanol and higher concentrations of ammonium sulfate to the staining solution previously described [1]. The method combines the advantage of much shorter staining time with high sensitivity, a clear background not requiring destaining, stepwise staining, and stable fixation after staining. The method has been applied to staining of polyacrylamide gels after sodium dodecyl sulfate‐electrophoresis and isoelectric focusing in carrier ampholyte‐generated pH gradients.