Binding of sulforhodamine B to human serum albumin: A spectroscopic study

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• 作者：Masanori Kitamura ; Koji Murakami ; Kohei Yamada ; Keiichi Kawai ; Munetaka Kunishima
• 关键词：Sulforhodamine B ; Human serum albumin ; Fluorescence ; Fluorescence quenching ; Circular dichroism ; Albumin
• 刊名：Dyes and Pigments
• 出版年：December, 2013
• 年：2013
• 卷：99
• 期：3
• 页码：588-593
• 全文大小：683 K

文摘

Sulforhodamine B (SRB) is a widely used fluorescent dye in biological sciences including in聽vivo studies. In this study, the binding interaction between SRB and human serum albumin (HSA) was investigated by fluorescence and circular dichroism spectroscopy. Complexation with HSA leads to an increase in dye fluorescence, from which the binding constant (1.6聽脳聽10⁵聽M^鈭? at 25聽掳C), binding stoichiometry (1:1), and thermodynamic parameters of the SRB-HSA interaction (螖H聽=聽5.2聽kJ/mol, 螖S聽=聽116.5聽J/mol聽K) were obtained. The large positive 螖S and the small positive 螖H indicate an entropy-driven binding process, suggesting that SRB binds to Sudlow site I of HSA by a dominant hydrophobic interaction. Circular dichroism revealed some degree of conformational changes in HSA upon binding.