Coomassie Brilliant Blue G-250, 5g

Coomassie® Brilliant Blue G-250 is a useful dye for SDS gels as it readily stains proteins with minimal background color. Protein bands can be visualized during staining. Coomassie Brilliant Blue G-250 is a protein stain in electrophoresis. Brilliant Blue G has been used in the Bradford dye-binding protein assay. A mechanism for dye binding to protein has been proposed, based on measuring Coomassie Brilliant Blue G-250 (CBBG) absorbance spectra during titration of the dye reagent in the absence of protein and its response to different polyamino acids. Brilliant Blue G has been used for determining critical micelle concentration of detergents. The CBBG dye reagent can exist in three forms: a cation (red form with maximum absorbance at 470 nm), a neutral form (green with maximum at 650 nm), and an anionic form (blue with maximum at 595 nm). The latter forms a stable complex with basic amino acid residues of proteins, mainly with arginine and aromatic amino acids. Although the anionic form exists in negligible concentration at the pH of the assay reaction mixture, the binding to protein shifts the equilibrium toward its formation.