头孢曲松钠与胃蛋白酶相互作用的光谱研究

Spectroscopic Study on the Interaction Between Ceftriaxone Sodium and pepsin

在不同温度下利用荧光光谱、紫外吸收光谱等方法研究胃蛋白酶与头孢曲松钠之间的相互作用.计算两者的结合常数K和结合位点数n,判断头孢曲松钠对胃蛋白酶荧光猝灭机制为动态猝灭.由热力学参数ΔG<0,ΔH>0且ΔS>0,表明结合过程是自发进行且两者之间的作用力主要是疏水作用力.通过F?rster偶极-偶极非辐射能量转移机理确定头孢曲松钠在胃蛋白酶中与色氨酸残基之间距离R为0.92 nm.

The interaction between ceftriaxone sodium and pepsin was investigated by spectrophotometric techniques such as fluorescence and UV-vis absorption at different temperatures.The binding constant K and the number of binding site n of the system were calculated.The results showed that ceftriaxone sodium has a strong quenching on the intrinsic fluorescence of pepsin through a dynamic quenching procedure.The nega？tive value of G0 reveals that the binding process is a spontaneous process and the positive value of ΔH/ΔS in？dicates that the binding power between them is mainly hydrophobic bond.It was determined that the distance between ceftriaxone sodium and tryptophan residues in pepsin is 0.92 nm by the mechanism of non-radiation energy transfer.