中文摘要：

纳米TiO2已在各领域得到广泛应用，由于其小尺寸效应、表面效应、量子尺寸效应等性质因而具有很强的生物学效应，易进入人体内，因而担心对人的健康构成潜在危害作用，但其作用机制不明朗．通过体内和体外实验相结合的研究方法，运用光谱学的手段，研究了纳米TiO2颗粒与乙酰胆碱酯酶（ACHE）结构-功能的作用关系．结果表明，在体内，随着纳米TiO2颗粒处理剂量的增加，AChE活性明显增加．在体外，一定浓度范围内纳米TiO，颗粒对AChE有显著的激活作用．光谱学分析证实纳米TiO2颗粒与AChE直接发生结合作用，强结合位点数为1．6个，结合常数为2．56×10^7L·mol^-1,而弱结合位点的结合常数为3．06×10^6L·mol^-1．过多纳米TiO2颗粒的结合将导致AChE去折叠并破坏其二级结构．提示纳米TiO2颗粒处理引起小鼠体内AChE活性的变化可能与纳米TiO2颗粒结合后引起AChE的结构变化有密切关系．

英文摘要：

TiO2 nanoparticles have increasingly been used in the various fields. However, it is these unique characteristics such as small sizes, large surface per mass, and high reactivity that TiO2 nanoparticles can enter the human body quickly and then imposes potential risks on human health. In order to study the mechanisms underlying the effects of TiO2 nanoparticles on acetylcholine esterase （ACHE, EC3.1.1.7） of mice, ICR mices were injected with TiO2 nanoparticles （5 nm） of various doses into the abdominal cavity daily for 14 d. We then examined AChE activity in vivo and in vitro and directly evident for interaction be- tween TiO2 nanoparticles and AChE using spectral methods. The results showed that TiO2 nanoparticles could significantly activate AChE in vivo and in vitro. By spectral assays, the TiO2 nanoparticles were de- termined to be directly bound to ACHE, AChE had 1.6 strong binding sites for TiO2 nanoparticles, and their binding constants of the binding sites were 2.56 X 107 L-mol^-1, while the binding constants were 3.06 × 10^6 L.mol^-1 for the weak binding sites. And TiO2 nanoparticles induced the protein unfolding and secondary structure damage of ACHE. It was concluded that the binding of TiO2 nanoparticles altered AChe structure and function.