Interactions of anionic detergents with cationic residues

Interaction of Anionic Detergents with Cationic Residues in Polypeptides... 

Found that the anionic form of the Coomassie dye reacts primarily with arginine residues within the macro molecular protein. Coomassie dye reacts to a lesser extent with other basic amino acid residues (His, Lys) and aromatic residues (Try, Tyr, Phe) present in macromolecularproteins, but not with the free amino acids. Dye binding is attributed to van der Waals forces and hydrophobic interactions. The interference seen with bases, detergents, and other compounds can be explained by their effects upon the equilibrium between the three dye forms (cationic, neutral, anionic). 

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