计算机模拟和光谱法研究头孢他美酯与胃蛋白酶的结合机理

采用多种光谱法及计算机模拟技术研究了298，303，310 K温度下，头孢他美酯（CFP）与胃蛋白酶（PEP）之间的结合机理。结果表明，CFP主要以非辐射能量转移的静态猝灭方式猝灭PEP的荧光，两者主要通过静电作用力结合，其结合率在310 K为74.73%~92.13%。采用同步荧光法和圆二色谱法研究CFP对PEP的反应，结果表明两者的结合诱导了PEP的构象变化，使PEP的内源荧光猝灭。采用计算机模拟CFP与PEP的对接，结果表明CFP结合在PEP的催化活性位点处，该结论与光谱法所得结果一致。利用CFP对PEP的荧光猝灭反应，可以实现对实际药品中CFP含量的快速测定。

Study of Interaction Between Cefetamet Pivoxil and Pepsin by Spectroscopic and Molecular Docking

The interaction of cefetamet pivoxil (CFP) and pepsin (PEP) has been investigated by fluorescence spectra, synchronous fluorescence spectra, UV-Vis absorption spectra, circular dichroism (CD) spectra and molecular docking method at 298, 303 and 310 K. The results indicate that CFP mainly uses the static quenching method of nonradiative energy transfer to cause the fluorescence quenching of PEP, which is mainly combined by static electricity forces. The binding rate is 74.73%-92.13% at 310 K. The effect of CFP on PEP structure was studied by synchronous and circular dichroism (CD). The results show that the binding of CFP and PEP induces the conformational change of PEP, and quenches the endogenous fluorescence in PEP. The results of molecular docking reveal that CFP locates in the catalytic active site of PEP, and the results of docking are consistent with that of experimental calculation. It is confirmed that the addition of CFP leads to the gradual quenching of PEP fluorescence. The fluorescence quenching reaction of CFP to PEP can be used to determine the content of CFP in the medicine.