Coomassie blue R-250 is a dye that is commonly used in laboratories to stain or quantify proteins. It is a sensitive stain for protein detection in polyacrylamide gels, typically giving blue bands on a clear background with a sensitivity of 50-100 ng/band. It may be combined with other stains, such as silver stain, to distinguish different types of proteins. Coomassie blue R-250 displays metachromasia by appearing pink-red, rather than blue, when binding certain proteins, such as collagen and histone H1.
