Binding of Heavy Metals with C-Phycocyanin: A Comparison between Equilibrium Dialysis, Fluorescence and Absorption Titration

Abstract

The energetic of interaction of metal ions with C-Phycocyanin (C-PC) Spirulina platensis were investigated using optical and thermodynamic methods. Comparison of the binding constants of heavy metals with C-PC by the instrumentality of difference methods shown, that binding affinities of toxic and heavy metal ions for C-PC strongly depend upon the metal. The efficiency of interaction for different metals is arranged in the same sequence for the absorption titration as it is for fluorescence. Obtained results using equilibrium dialysis are in good agreement with results using fluorescence spectroscopy in the case Ag+, but difference is observed for Ni2+ and Cr3+ ions.