Mechanism of dye response and interference in the Bradford protein assay

摘要: Bradford Coomassie brilliant blue G-250 protein-binding dye exists in three forms: cationic, neutral, and anionic. Although the anion is not freely present at reagent pH, it this form that complexes with protein. Dye binding requires a macromolecular certain reactive functional groups. Interactions are chiefly arginine rather than primary amino groups; other basic (His, Lys) aromatic residues (Try, Tyr, Phe) give slight responses. The behavior attributed to Van der Waals forces hydrophobic interactions. Assay interference by bases, detergents, compounds explained terms of their effects upon equilibria between forms.