Interaction studies of copper complex containing food additive carmoisine dye with human serum albumin (HSA): Spectroscopic investigations |
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| Authors: | Nahid Shahabadi Alireza Akbari Mina Jamshidbeigi Soraya Moradi Fili |
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| Affiliation: | 1. Department of Inorganic Chemistry, Faculty of Chemistry, Razi University, Kermanshah, Iran;2. Medical Biology Research Center (MBRC), Kermanshah University of Medical Sciences, Kermanshah, Iran;3. Department of Chemistry, Payame Noor University, Tehran, Iran |
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| Abstract: | In this study, the interaction between human serum albumin (HSA) and a copper complex of carmoisine dye; Cu(carmoisine)2(H2O)2], was studied in vitro using multi‐spectroscopic methods. It was found that the intrinsic fluorescence of HSA was quenched by the addition of the Cu(carmoisine)2(H2O)2] complex and the quenching mechanism was considered as static quenching by formation of a Cu(carmoisine)2(H2O)2]–HSA complex. The binding constant was about 104 M?1 at room temperature. The values of the calculated thermodynamic parameters (ΔH < 0 and ΔS > 0) suggested that both hydrogen bonds and the hydrophobic interactions were involved in the binding process. The site marker competitive experiments revealed that the binding of Cu(carmoisine)2(H2O)2] to HSA primarily occurred in subdomain IIIA (site II) of HSA. The results of circular dichroism (CD) and UV–vis spectroscopy showed that the micro‐environment of amino acid residues and the conformation of HSA were changed after addition of the Cu(carmoisine)2(H2O)2] complex. Finally, the binding of the Cu(carmoisine)2(H2O)2] complex to HSA was modelled by a molecular docking method. Excellent agreement was obtained between the experimental and theoretical results with respect to the binding forces and binding constant. |
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| Keywords: | carmoisine dye copper(II) complex fluorescence spectroscopy human serum albumin (HSA) |
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