苯丙氨酸与肾上腺素相互作用的伏安特性及理论研究

发布时间：2018-10-25 17:28

【摘要】： 蛋白质是生命的物质基础,没有蛋白质就没有生命。它是与生命、与各种形式的生命活动紧密联系在一起的物质。组成蛋白质的基本单位是氨基酸,氨基酸是构建生物机体的众多生物活性大分子之一,是构建细胞、修复组织的基础材料。肾上腺素是哺乳动物和人类的一种重要的儿茶酚胺类神经传递物质,它控制着神经系统进行一系列生物反应及神经化学过程。研究氨基酸分子与肾上腺素的相互作用,对于推动生命科学、药物化学、物理化学等学科的发展能起到一定的积极作用。本文用电化学方法研究了甘氨酸、丝氨酸、谷氨酸、天冬氨酸、苯丙氨酸五种氨基酸对肾上腺素电化学氧化的影响,着重讨论了苯丙氨酸对肾上腺素电化学行为的影响,并辅助于量子化学方法对苯丙氨酸与肾上腺素形成的氢键复合物进行了理论探讨。首先,利用循环伏安法研究了甘氨酸、丝氨酸、谷氨酸、天冬氨酸、苯丙氨酸在盐酸体系中对肾上腺素电子转移性质的影响,实验结果表明:这几种氨基酸对肾上腺素具有一定的稳定作用,能在一定程度上抑制肾上腺素的氧化,从而改变了肾上腺素的循环伏安特征,并且氨基酸的结构对肾上腺素的氧化能力有一定影响。盐酸溶液中,不同结构的氨基酸抑制肾上腺素氧化的能力顺序为:甘氨酸＜丝氨酸＜谷氨酸＜天冬氨酸＜苯丙氨酸。其次,选用不同pH、不同的溶液组成及铂电极、玻碳电极,利用循环伏安法研究了苯丙氨酸在盐酸体系中对。肾上腺素电子转移性质的影响。实验结果表明:在不同pH的盐酸体系、盐酸.氯化钠缓冲溶液体系、B.R.缓冲溶液以及pH=7.4的生理介质KRPB中,苯丙氨酸均对肾上腺素具有一定的稳定作用,能在一定程度上抑制肾上腺素的氧化。随着pH的增大、苯丙氨酸浓度的增大,肾上腺素氧化峰电位正移,还原峰电位负移,峰电流减小,肾上腺素的循环伏安特征以此发生了改变。最后,用量子化学方法中的DFT-B3LYP方法对苯丙氨酸与肾上腺素分子间的氢键作用作了理论研究,优化了苯丙氨酸与肾上腺素形成氢键复合物的几何构型,对形成的各种氢键复合物通过比较成键前后的一系列参数进行了理论探讨。气相中苯丙氨酸能与肾上腺素形成9种1:1氢键复合物,液相中则是形成5种。氢键的形成对肾上腺素的羟基起到了保护作用,使其苯环上相邻的羟基(-OH)上的H难以脱去,降低了体系的能量,增加了肾上腺素的稳定性,在一定程度上抑制了肾上腺素的氧化,并且结合结构参数和能量,解释了有关实验现象。
[Abstract]:Protein is the material foundation of life, without which there is no life. It is a substance closely associated with life, with all forms of life. The basic unit of protein is amino acid, which is one of the bioactive macromolecules in the construction of biological organism. It is the basic material to construct cells and repair tissues. Epinephrine is an important catecholamine neurotransmitter in mammals and humans. It controls a series of biological reactions and neurochemical processes in the nervous system. The study of the interaction between amino acid molecules and epinephrine can play a positive role in promoting the development of life science, drug chemistry, physical chemistry and so on. The effects of glycine, serine, glutamic acid, aspartic acid and phenylalanine on the electrochemical oxidation of epinephrine were studied by electrochemical method. The hydrogen bond complex formed by phenylalanine and epinephrine was studied theoretically by means of quantum chemical method. Firstly, the effects of glycine, serine, glutamate, aspartic acid and phenylalanine on the electron transfer properties of epinephrine in hydrochloric acid system were studied by cyclic voltammetry. The results show that these amino acids can stabilize epinephrine to a certain extent and inhibit the oxidation of epinephrine to a certain extent, thus changing the cyclic voltammetry of epinephrine. The structure of amino acids has a certain effect on the oxidation ability of epinephrine. In hydrochloric acid solution, the order of the ability of amino acids with different structures to inhibit the oxidation of epinephrine was glycine < serine < glutamic acid < aspartic acid < phenylalanine. Secondly, phenylalanine in hydrochloric acid system was studied by cyclic voltammetry with different pH, solution composition, platinum electrode and glassy carbon electrode. The effect of epinephrine electron transfer properties. The results show that in different pH hydrochloric acid systems, hydrochloric acid. Sodium chloride buffer solution system, B.R. In buffer solution and KRPB, the physiological medium of pH=7.4, phenylalanine can stabilize epinephrine to some extent and inhibit the oxidation of epinephrine to some extent. With the increase of pH, the concentration of phenylalanine increases, the peak potential of epinephrine oxidation is shifted positively, the peak potential of reduction shifts negatively, the peak current decreases, and the cyclic voltammetry of epinephrine changes. Finally, the hydrogen bond between phenylalanine and epinephrine was studied theoretically by the DFT-B3LYP method in quantum chemistry, and the geometric configuration of the hydrogen bond complex between phenylalanine and epinephrine was optimized. A series of parameters before and after bonding are discussed theoretically. Phenylalanine can form nine 1:1 hydrogen bond complexes with epinephrine in gas phase and 5 in liquid phase. The formation of hydrogen bond protects the hydroxyl group of epinephrine, which makes it difficult to remove H from the adjacent hydroxyl group (- OH) on the benzene ring, which decreases the energy of the system and increases the stability of epinephrine. The oxidation of epinephrine was inhibited to some extent, and the experimental phenomena were explained by combining the structural parameters and energy.
【学位授予单位】：曲阜师范大学
【学位级别】：硕士
【学位授予年份】：2009
【分类号】：R341

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