荧光猝灭法研究依诺沙星和蛋白质的相互作用

Interaction of Enoxacin with Albumins by Fluorescence Quenching Analysis

采用荧光光谱法、分光光度法研究了水溶液中依诺沙星与牛血清白蛋白 (BSA)和鸡蛋清白蛋白(CEA)的相互结合反应。依诺沙星与 2种蛋白质均以摩尔比 1∶1牢固结合 ,结合反应平衡常数分别为KBSA=8 0 2× 10 4L/mol和KCEA=4 5 1× 10 4L/mol。根据F rster非辐射能量转移机理 ,计算了依诺沙星与牛血清白蛋白和鸡蛋清白蛋白给体 受体间距离r分别为 2 5 2和 2 74nm ,能量转移效率E分别为 0 5 4和 0 5 2。证实了依诺沙星与牛血清白蛋白和鸡蛋清白蛋白的相互结合作用为单一的静态猝灭过程 。

The binding reactions of enoxacin with bovine serum albumin(BSA) or chicken egg albumin(CEA) in aqueous solution were studied by fluorescence and UV-Vis absorption spectrometry. The results indicated that enoxacin could bind with BSA or CEA strongly at molar ratio 1∶1 and the equilibrium constants were K BSA=8.02×10 4 L/mol and K CEA=4.51×10 4 L/mol, respectively. The action distances(r BSA= 2.52 nm, r CEA=2.74 nm) and energy transfer efficiencies(E BSA=0.54, E CEA=0.52) between donor(BSA,CEA) and acceptor(enoxacin) were calculated according to Frster′s nonradiative energy transfer mechanism. Good linear Stern-Volmer lines were observed on the fluorescence of BSA or CEA quenched by enoxacin of different concentration, indicating the combination reaction of enoxacin with BSA or CEA is a single static quenching process.