Spectroscopic investigation on the interaction of some polymer-cobalt(III) complexes with serum albumins

The interaction between the polymer-cobalt(III) complexes, [Co(dien)(phen)BPEI]Br3·2H2O and [Co(phen)2(BPEI)Cl]Cl2·4H2O (where phen is 1,10- phenanthroline, dien is diethylenetriamine, BPEI is branched polyethyleneimine) and serum albumins is studied using steady state fluorescence, lifetime measurement and circular dichroism spectroscopy techniques under physiological condition. The analysis of fluorescence data indicates the presence of static quenching mechanism in the binding process. Various binding parameterss including thermodynamic parameters ΔH°, ΔS° and ΔG° have been evaluated. The quantitative analysis of CD spectra reveals information on the changes in the content of the α-helix of the HSA/BSA upon binding.