依诺沙星与牛血清白蛋白相互作用的荧光法研究

Investigation of the Interaction between Enoxacin and Bovine Serum Albumin by Fluorescence

用荧光光谱法研究了新型氟喹诺酮药物依诺沙星与牛血清白蛋白的相互作用机制。求得它们在16℃和26℃温度下的结合常数分别为K1=9.0×103 和K2=1.73×103,结合位点数分别为n1=0.89和n2=0.74。根据不同温度时的结合常数 ,求得依诺沙星与牛血清白蛋白的热力学参数(26℃) :ΔHm= -51.44kJ/mol,ΔGm= -8.05kJ/mol,ΔSm= -0.145kJ/(mol·K)。根据F rster非辐射能量转移机制 ,测定了实验条件下依诺沙星与牛血清白蛋白相互结合时 ,能量给体 -受体间的作用距离(r=4.74nm)和能量转移效率(E=0.074) ,并用同步荧光技术考察了依诺沙星对牛血清白蛋白构象的影响。实验表明 ,依诺沙星与牛血清白蛋白分子间有较强的结合作用 。

The mechanismofinteractionbetweenenoxacin(ENX)and bovine serumalbumin(BSA)was investiˉgated with fluorescence spectrometry.Their binding constants are K 1 =9.0×10 3 and K 2 =1.73×10 3 ,and the numbers of binding sites are n 1 =0.89and n 2 =0.74,respectively,at16℃and26℃.At26℃,the thermodynamic parameters of interaction between ENX and BSA areΔH m =-51.44kJ/moL,ΔG m =-8.05kJ/moL,andΔS m =-0.145kJ/(mol·K).The binding distance(r=4.74nm)and transfer efficiency(E=0.074)between ENX and BSA were obtained according to the theory of F⒐rster non-radiation energy transfer.The effect of enoxacin on the conformation of BSA was also analyzed using synchronous fluorescence spectrometry.The experiments showed that there is strong interaction between ENX and BSA,and the main dominant sorts of binding forces are hydrogen bond and Van der Waals′interaction.