碳纳米材料修饰电极研究铝形态化合物对几种生物酶活性的影响

发布时间：2018-01-09 20:19

本文关键词：碳纳米材料修饰电极研究铝形态化合物对几种生物酶活性的影响　出处：《南京师范大学》2012年硕士论文　论文类型：学位论文

【摘要】：铝在环境中主要以硅酸盐和氧化物的形式存在于矿物中,由于近年来酸雨等各种环境问题使得湖泊、河流、土壤等发生不同程度的变化,致使铝从岩石和土壤中溶解出来,以多种可影响生物活性的形态存在。研究证实,铝能够抑制三羧酸循环和糖酵解过程中各种酶的活性,从而严重阻碍亚细胞线粒体供能系统正常运行。通过多种途径进入人体内的铝会导致一系列疾病,如贫血症、骨软化病,尤其是阿尔兹海默症、帕金森症等神经系统疾病。因此,研究铝元素形态对人类健康生活有很重要的意义。人们已经发现纳米颗粒会对自然环境和人类健康造成许多无法预计的潜在威胁,开始越多关注纳米颗粒的安全性问题。本论文采用碳纳米管修饰电极研究纳米形态及其他铝形态化合物对依赖于辅酶Ⅱ (NADP+/NADPH)的谷胱甘肽还原酶(GR)活性的影响,并利用圆二色谱法研究其相互之间的影响机制：采用还原型石墨烯修饰电极探究铝形态化合物对依赖辅酶Ⅰ (NAD+/NADH)的乙醛脱氢酶(ALDH)和乙醇脱氢酶(ADH)活性的作用,并采用化学计算方法作了进一步讨论。实验结果如下所述： 1.采用滴涂法制备碳纳米管MWNTs/壳聚糖CHIT修饰玻碳电极和还原型石墨烯rGO/CHIT修饰电极,MWNTs/CHIT修饰电极和rGO/CHIT电极分别较为明显的降低了还原型辅酶Ⅱ (NADPH)和辅酶Ⅰ(NADH)在裸的玻碳电极上的氧化过电位,利用计时电流i-t法,通过检测NADPH和NADH在电极上催化电流的变化情况,分别实验不同形态铝化合物对GR、ALDH、ADH活性的影响。实验结果发现,铝对GR和ALDH、ADH的活性均具有一定的抑制作用。 2.不同的铝形态及溶液pH值,对酶活性影响也不同。当缓冲液的pH7时,Al(Ⅲ)对GR、ALDH和ADH活性抑制作用最为明显,并且随着体系pH值增大,抑制作用减小。这是因为溶液在较低pH下,能够与GR体系相互作用的Al3+是其主要的存在形态。相对应地,缓冲液的pH接近7时,Al13的存在对GR、ALDH和ADH活性抑制作用最为明显的酸度条件。这可归因于此酸度下Al13最稳定,而在偏酸和偏碱的条件下由于Al13聚合度降低而导致其不稳定。 3.选择圆二色谱手段研究了Al(Ⅲ)和Al13对GR活性的影响机制,结果发现Al(Ⅲ)和Al13能够使得GR的构象发生变化。另外采用荧光光谱和量子化学计算等多种手段研究了Al(Ⅲ)和Al13对ADH酶活性改变可能的作用方式和机制,实验结果表明Al(Ⅲ)和Al13能够同时引起ADH和NAD+自身的构象发生变化。量子化学计算结果表明,Al、F之间的配位作用会导致ADH构象的变化。Al(Ⅲ)和Al13诱导引起的NAD+和ADH构象变化是引起ADH活性改变的最重要因素。
[Abstract]:Aluminum in the environment mainly exists in the form of silicate and oxide minerals, due to acid rain and other environment makes the lakes, rivers, change in different degrees of soil, resulting in aluminum dissolved out from rock and soil, with a variety of existing biological activity form influence. The research shows that, the aluminum can be a variety of enzymes inhibition of three citric acid cycle and glycolysis activity, which seriously hinder the mitochondrial cell energy supply system to normal operation. Into the body of the aluminum through a variety of ways will lead to a series of diseases, such as anemia, bone softening diseases, especially Alzheimer's disease, Parkinson's disease and other diseases of the nervous system. Therefore, the research of aluminum speciation is very important for human health. It has been found that nanoparticles will cause many potential threats to the natural environment and human health, more attention to The safety problem of nanoparticles. The carbon nanotube modified electrode of nano morphology and other forms of aluminum compounds on NADPH dependent on the glutathione reductase (NADP+/NADPH) (GR) activity, and using the research method of two round chromatography the mutual influence mechanism of the reduced graphene modified electrode probe compounds the forms of aluminum dependence on NAD (NAD+/NADH) aldehyde dehydrogenase (ALDH) and alcohol dehydrogenase (ADH) activity, and the chemical calculation method is further discussed. The experimental results are as follows:
1. by drop coating method for preparing carbon nanotubes MWNTs/ chitosan CHIT modified glassy carbon electrode and reduced graphene rGO/CHIT modified electrode, MWNTs/CHIT modified electrode and rGO/CHIT electrode was obviously reduced by NADPH and NADH (NADPH) (NADH) on a glassy carbon electrode electrochemical oxidation of bare over potential use the current time by I-T method to detect the change of NADPH and NADH in the catalytic electrode current, respectively. Experimental ALDH different aluminum compounds on GR, and influence the activity of ADH. The experimental results show that the aluminum of GR and ALDH, the activity of ADH has certain inhibitory effect.
2. different forms of aluminum and pH value of the solution, effect on enzyme activity is different. When the buffer pH7, Al (III) on GR, ALDH and ADH activity inhibition is most obvious, and with the pH value of the system increased, inhibition decreases. This is because the solution at low pH, and can GR the interaction of Al3+ is the main form. Correspondingly, the buffer pH is close to 7, Al13 to GR, ALDH and ADH inhibitory activity of the most obvious acidity condition. This can be attributed to the acidity of Al13 was the most stable in partial acid and alkali conditions the Al13 degree of polymerization decreased and cause instability.
3. select the circle two chromatography was studied by means of Al (III) and the influence mechanism of Al13 on the activity of GR, the results showed that Al (III) and Al13 can cause conformational changes in the GR. In addition Al was studied by fluorescence spectroscopy and quantum chemical calculation means (III) and Al13 on the activity of ADH to change the mode of action and the possible mechanism, the experiment results show that the Al (III) and Al13 can also cause the conformation of ADH and NAD+'s own change. Quantum chemical calculation results show that Al F, the coordination interaction between.Al leads to changes in the conformation of ADH (III) and Al13 induced NAD+ and ADH conformational change is the cause of the most important ADH activity changes.

【学位授予单位】：南京师范大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R3411

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