The Interaction and Thermodynamic Studies on the Binding of Congo Red Dye with Collagen Protein by Polarographic and Equilibrium Dialysis Techniques

Abstract

Abstract The survey of the existing literature revealed that the binding of Molybdenum, Vanadium, Zinc, Cadmium, Copper, Nickel and Cobalt with the protein is well known but no binding studies of Congo red molecules with collagen are reported. With a view to extend the existed knowledge of ecological nature of dye-protein system, it was thought of interest to investigate of properties of dye-protein mixture. The binding of Congo red dye has been studied with collagen protein using polarographic and equilibrium dialysis techniques. The intrinsic association constants and the number of binding sites have been calculated from Scatchard plots. The effect of pH on these constants was studied at pH 5.57, 7.50, 9.50 by polarographic technique and it was found that these values were decreased with increasing pH. The effect of pH was found to be similar by equilibrium dialysis technique. The values of different thermodynamic parameters have been reported. The free energies of aggregation, ΔG associated with the binding interaction of the dyes and protein were calculated. The negative values of the ΔG confirm the feasibility of interaction between the dye and protein.