应用荧光猝灭法研究尼莫地平与牛血清白蛋白的相互作用

应用荧光光谱(FS)和紫外光谱(UV)研究了尼莫地平与牛血清白蛋白(BSA)之间的相互作用。尼莫地平与BSA的结合常数K_A为5.01×104(26 ℃)和4.46×104(36 ℃)，尼莫地平在BSA上的结合位点数为1.08±0.01。根据Frster非辐射能量转移理论，求出了尼莫地平与BSA之间的结合距离为3.14 nm(26 ℃)和3.10 nm(36 ℃)。实验表明静态猝灭和非辐射能量转移是 导致尼莫地平对BSA荧光猝灭的两大原因。通过计算热力学参数，可知该药物与牛血清白蛋白的相互作用是一个吉布斯自由能降低的自发过程，且二者之间的作用力以静电相互作用为主。

Study on the Interaction of Nimodipine and Bovine Serum Albumin by Fluorescence Quenching Method

The interaction of Nimodipine and bovine serum albumin (BSA) was studied using fluorescence spectroscopy (FS) and ultraviolet spectroscopy (UV). The apparent binding constants (K_A) between Nimodipine and BSA were 5.01×104(26 ℃) and 4.46×104(36 ℃), and the binding sites (n) were 1.08±0.01. According to the Frster theory of non-radiation energy transfer, the binding distances (r) were also obtained. The experimental results showed that Nimodipine could quench the inner fluorescence of BSA by forming the Nimodipine-BSA complex. It was found that both static quenching and non-radiation energy transfer led to the fluorescence quenching. The process of binding was a spontaneous molecular interaction in which entropy increased while Gibbs free energy decreased. The thermodynamic parameters indicated that the interaction of Nimodipoine and BSA was driven mainly by static electrical force.