| Abstract: | Binding of an azo dye, 4′-dimethyl amino azo benzene-4-carboxylic acid (DAAC) to poly(L -lysine) (PLL) in basic aqueous solutions at 20°C has been studied. The azo dye was found to bind to PLL when its side-chain amino groups are in the uncharged state. This was found to be a cooperative phenomenon, and the binding constant and cooperativity factor have been evaluated. The binding of the dye was found to result in a conformational transition of PLL from the α-helix to the β-sheet, which in turn helps in increased dye binding. |
