On binding to a protein the negatively charged Coomassie Brilliant Blue G-250 dye molecule will give an overall negative charge to the protein. This property can be used to separate proteins or protein complexes using polyacrylamide gel electrophoresis under non-denaturing conditions in a technique called Blue Native PAGE.[20][21] The mobility of the complex in the polyacrylamide gel will depend on both the size of the protein complex (i.e. the molecular weight) and on the amount of dye bound to the protein.