An alternate mode of binding of the polyphenol quercetin with serum albumins when complexed with Cu(II)

Singha Roy, Atanu ; Tripathy, Debi Ranjan ; Ghosh, Arup Kumar ; Dasgupta, Swagata (2012) An alternate mode of binding of the polyphenol quercetin with serum albumins when complexed with Cu(II) Journal of Luminescence, 132 (11). pp. 2943-2951. ISSN 0022-2313

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Official URL: https://www.sciencedirect.com/science/article/pii/...

Related URL: http://dx.doi.org/10.1016/j.jlumin.2012.05.018

Abstract

Polyphenols find wide use as antioxidants, cancer chemopreventive agents and metal chelators. The latter activity has proved interesting in many aspects. We have probed the binding characteristics of the polyphenol quercetin–Cu(II) complex with human serum albumin (HSA) and bovine serum albumin (BSA). Fluorescence studies reveal that the quercetin–Cu(II) complex can quench the fluorescence of the serum albumins. The binding constant (Kb) values are of the order of 105 M−1 which increased with rise in temperature in case of HSA and BSA interacting with the quercetin–Cu(II) complex. Displacement studies reveal that both the ligands bind to site 1 (subdomain IIA) of the serum albumins. However, thermodynamic parameters calculated from temperature dependent studies indicated that the mode of interaction of the complexes with the proteins differs. Both ΔH° and ΔS° were positive for the interaction of the quercetin–Cu(II) complex with both proteins but the value of ΔH° was negative in case of the interaction of quercetin with the proteins. This implies that after chelation with metal ions, the polyphenol alters its mode of interaction which could have varying implications on its other physicochemical activities.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Quercetin–Cu(II) Complex; Serum Albumins; Fluorescence Studies; Binding; Circular Dichroism; UV–Vis Studies
ID Code:113763
Deposited On:15 May 2018 06:23
Last Modified:15 May 2018 06:23

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