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

The interaction of HSA/BSA with single and double chain surfactant-cobalt(III) complexes, cis-[Co(phen)2(UA)Cl](ClO4)2·2H2O (1), cis-[Co(phen)2(UA)2](ClO4)3·2H2O (2), cis-[Co(en)2(UA)Cl](ClO4)2·2H2O (3), cis-[Co(en)2(UA)2](ClO4)3·2H2O (4), were investigated by steady state fluorescence, UV-vis absorption, synchronous, three dimensional fluorescence and circular dichroism spectroscopy. The results reveal that the quenching of HSA/BSA by all the four complexes takes place through static mechanism. The binding constant, binding sites and thermodymamic parameter were calculated. The results illustrate that the double chain surfactant-cobalt(III) complexes bind more strongly than the corresponding single chain complexes. The distance between donor (HSA/BSA) and acceptor (surfactant-cobalt(III) complexes) was obtained according to FRET. The results of synchronous, three dimensional and circular dichroism spectroscopy studies show that all the complexes caused considerable amount of conformational and some amount of environment changes in HSA/BSA.