pH-insensitive electrostatic interaction of carmoisine with two serum proteins: A possible caution on its uses in food and pharmaceutical industry

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• 作者：Shubhashis Datta ; Niharendu Mahapatra ; Mintu Halder ; ^{mintu@chem.iitkgp.ernet.in}
• 关键词：Carmoisine ; Serum proteins ; Fluorescence quenching ; Specific binding ; Thermodynamic parameters
• 刊名：Journal of Photochemistry and Photobiology B: Biology
• 出版年：2013
• 出版时间：5 July, 2013
• 年：2013
• 卷：124
• 期：Complete
• 页码：50-62
• 全文大小：1645 K

文摘

Here we have investigated the binding of carmoisine, a water-soluble azo food colorant, with serum proteins (HSA and BSA) by fluorescence and UV-VIS spectroscopy, circular dichroism and molecular docking studies. Results indicate that fluorescence quenching of protein has been due to site-specific binding of the dye with biomacromolecules. Site marker competitive binding and molecular docking explorations show that interaction occurs in the sub-domain ??A of HSA and the sub-domains ??A and ?B in the case of BSA. Conformational investigation indicates that dye binding modifies the secondary structure of proteins and this also alters the microenvironment of the tryptophan(s). The interaction is found to be pH-insensitive which can have relevance to the toxicological profiles of the dye, and ionic strength dependence of binding can be exploited in protein purification mediated by such food colorants.