Université de Toulouse 3, UPS, UMR 152 (Laboratoire de pharmacochimie des substances naturelles et pharmacophores redox), F-31062 Toulouse cedex 9, France.
Biomacromolecules. 2010 Dec 13;11(12):3341-51. doi: 10.1021/bm100814n. Epub 2010 Nov 16.
The binding affinity of human serum albumin (HSA) to three antimalarial indolone-N-oxide derivatives, INODs, was investigated under simulated physiological conditions using fluorescence spectroscopy in combination with UV-vis absorption and circular dichroism (CD) spectroscopy. Analysis of fluorescence quenching data of HSA by these compounds at different temperatures using Stern-Volmer and Lineweaver-Burk methods revealed the formation of a ground state indolone-HSA complex with binding affinities of the order 10(4) M(-1). The thermodynamic parameters ΔG, ΔH, and ΔS, calculated at different temperatures, indicated that the binding reaction was endothermic and hydrophobic interactions play a major role in this association. The conformational changes of HSA were investigated qualitatively using synchronous fluorescence and quantitatively using CD. Site marker competitive experiments showed that the binding process took place primarily at site I (subdomain IIA) of HSA. The number of binding sites and the apparent binding constants were also studied in the presence of different ions.
采用荧光光谱法并结合紫外可见吸收光谱法和圆二色性（CD）光谱法，在模拟生理条件下研究了三种抗疟吲哚啉-N-氧化物衍生物（INODs）与人血清白蛋白（HSA）的结合亲和力。使用 Stern-Volmer 和 Lineweaver-Burk 方法分析这些化合物在不同温度下对 HSA 的荧光猝灭数据，结果表明形成了一个基态吲哚啉-HSA 配合物，其结合亲和力约为 10(4) M(-1)。在不同温度下计算的热力学参数ΔG、ΔH 和 ΔS 表明，结合反应是吸热的，疏水相互作用在这种缔合中起主要作用。使用同步荧光法和 CD 法对 HSA 的构象变化进行了定性和定量研究。位点标记竞争实验表明，结合过程主要发生在 HSA 的位点 I（亚域 IIA）上。还研究了在存在不同离子时的结合位点数和表观结合常数。
