Thermodynamic analysis of human serum albomin interactions with a potent anti-cancer metallodrug

It has been seen that the distribution, free concentration and the metabolism of various small moleculessuch as drugs can be significantly altered as a result of their binding to human serum albumin (HSA) [1,2]. Therefore, the interaction of drugs with human serum albumin has major biochemical importance andcan be used as a model for elucidation of the drug’s protein complexation. In this research, a new zinc(II)complex [Zn(naph-dtc)(bpy)]Cl (where naph-dtc = naphthyldithiocarbamate and bpy = 2,2 -bipyridine)was synthesis and its interactions with Human serum albumin was studied by fluorescence and UV–Visspectroscopic methods under like physiological condition in Tris–HCl buffer solution at pH 7.4 and threetemperatures. Fluorescence data indicated that this Zn(II) complex strongly binds with HSA (Kb = 2.12 ×105 M-1) and this binding is characterized by one high affinity binding site (n ~ 1). The Stern–Volmeranalysis showed that the fluorescence quenching of protein by above complex resulted from staticmechanism. Corresponding thermodynamic parameters ΔG˚, ΔH˚ and ΔS˚ were calculated and revealedthat hydrophobic forces played a major role when Zn(II) complex interacted with HSA. The results ofUV–Vis spectra show that the secondary structure of the protein has been changed in the presence of thisZn(II) complex. Also, the distance between the acceptor, Zn(II) complex, and the donor, HSA, wasestimated on the basis of the Förster resonance energy transfer (FRET).

کلیدواژه ها:

Dithiocarbamate ، Zinc(II) complex ، Human serum albumin ، Spectroscopic measurements