A high-affinity protein stain for western blots, tissue prints, and electrophoretic gels.

A method for protein staining using copper phthalocyanine 3,4',4'',4'''-tetrasulfonic acid tetrasodium salt is described. The procedure is applicable to protein blots and tissue prints, as well as to polyacrylamide and agarose gels. It is also simple, involving only application of the stain and rinsing. For protein blots and tissue prints the staining is rapid, taking less than 1 min to completion, and more sensitive than any previously described dye-based nonspecific protein staining system. The staining is easily reversible, requiring only a change in pH to remove the dye.