Ciprofloxacin (CPFX) and enrofloxacin (ENFX), two of the most widely used fluoroquinolones (FQs), pose a great threat to humans and the ecosystem. In this study, the toxic mechanisms between the two FQs and trypsin were evaluated by means of multiple spectroscopic methods, as well as molecular docking. During the fluorescence investigations, both FQs quenched the intrinsic fluorescence of trypsin effectively, which was due to the formation of moderately strong complexes (mainly through van der Waals forces and hydrogen bonds). The binding of two FQs not only caused the conformational and micro-environmental changes of trypsin, but also changed its molecular activity; shown by the UV-Visible absorption spectroscopy, synchronous fluorescence spectroscopy, and functional tests. The established methods in this work can help to comprehensively understand the transport of FQs in the human body.

中文翻译：

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通过光谱和计算方法表征两种氟喹诺酮类药物对胰蛋白酶的毒性机制。

环丙沙星（CPFX）和恩诺沙星（ENFX）是使用最广泛的两种氟喹诺酮（FQ），对人类和生态系统构成了巨大威胁。在这项研究中，通过多种光谱方法以及分子对接的方法评估了两个FQ和胰蛋白酶之间的毒性机制。在荧光研究期间，两个FQ均有效地淬灭了胰蛋白酶的固有荧光，这是由于形成了中等强度的复合物（主要是通过范德华力和氢键）。两个FQs的结合不仅引起胰蛋白酶的构象和微环境变化，而且改变了其分子活性。由紫外可见吸收光谱，同步荧光光谱和功能测试显示。