Document Type : Article
Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
Department of Cell & Molecular Biology, Faculty of Biological Sciences, Kharazmi University, Tehran
Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
In pharmaceutical field, the effect of drugs on biological substances is of particular importance. Therefore, in this research, the interaction between human plasma carrier protein of Albumin (HSA) and a newly synthesized complex of Palladium(II) was tested by using site marker competitive tests and various spectroscopic methods such as ultraviolet, fluorescence, and circular dichroism (CD) at different temperatures of 25 and 37 °C.
The study of fluorescence spectroscopy showed that this complex reduced the inherent fluorescence emission of HSA, which was eventually quenched by the dynamic mechanism. As well, binding constants were calculated on the palladium compound. According to the obtained thermodynamic parameters of ΔHo and ΔSo values, it was shown that the interaction of palladium complex to the protein occurs via hydrophobic force. The analysis of the circular dichroism (CD) spectrum also showed that the palladium complex caused no significant changes in the secondary structure of the protein. The results of thermal stability of the protein in the presence of palladium complex showed a decreased in thermal stability of HSA.
Additionally, by the use of spectroscopic methods in the competitive experiments to identify the complex binding site on HSA using site marker competitive of warfarin for Sudlow’s site I, ibuprofen for Sudlow’s site II, and digitoxin for Sudlow’s site III were indicated. Competitive experiments have shown that palladium complex along with digitoxin have a common position on HSA at site III.