【作者】 伊万伟；

【导师】 浦铜良；

【作者基本信息】 兰州大学 ， 植物学， 2011， 硕士

【摘要】 羟基自由基（OH）是一种活泼的活性氧自由基,由于在高温高光强的环境条件下,植物体容易引发产生大量的高反应活性的-OH。一旦形成-OH,由于其极高的氧化活性,可以与生物体内的大分子发生高效、快速的反应,造成细胞内生物膜脂及其他生物大分子的氧化伤害。PAAC作为沙丘芦苇的特有内含物,分布于叶绿体中,前人研究发现,PAAC在高温高光强的胁迫下主要是通过高效、直接清除-OH来减轻膜脂和蛋白的氧化伤害从而适应这种逆境的,为进一步研究PAAC直接清除-OH的可能机制,本实验经过优化,利用紫外光解初始浓度为10mM的H₂O₂溶液提供外源-OH,在水溶液中,对PAAC在紫外光解过氧化氢体系中反应形成的各产物通过紫外光谱分析、TLC分析来确定PAAC清除-OH后自身结构是否发生变化,然后通过比色法测定其羟基和氨基含量的变化,结合红外光谱分析来探究其与-OH可能的作用机理。研究结果表明：PAAC在直接清除羟基自由（OH）的过程中,可能-OH与之发生了抽氢反应,引起了自身分子结构的变化,使得酚羟基和芳香伯氨基含量相对减少,羰基含量增加,这为进一步揭示PAAC清除羟基自由基的机制和抗氧化机理提供了实验依据和理论基础。更多还原

【Abstract】 Hydroxyl radical （OH） is one of the most lively and reactive oxygen radicals, under high temperature and light environmental conditions, the plant is apt to cause a large amount of highly reactive hydroxyl radical. Once the formation of hydroxyl radical in organisms, due to its high oxidation activity, it can react efficiently and rapidly with biological macromolecules, resulting in the oxidative damage of cell membrane lipids and other biological macromolecules.As a novel dune reed solute, PAAC is mainly distributed in the chloroplast. Through efficiently and directly scavenging of PAAC to OH and markedly suppressing the damage of lipid and protein, dune reed can adapt to high temperature and light environmental conditions. To further research the mechanism of PAAC scavenging OH, this experiment has been optimized to use UV photolysis of 10 mM initial concentration of H₂O₂ solution to provide foreign OH, we analysised the products of reaction system of PAAC in the UV photolysis of H₂O₂ by TLC,IR and MS to determine whether changes in its structure after PAAC scavenging OH. Then, we determined the changes of the hydroxyl and amino group content to explore the possible mechanism of PAAC scavenging OH with the results of infrared spectroscopy.The results show that,in the process of directly scavenging OH,PAAC may have made a H-atom abstraction reaction with OH, causing changes in its molecular structure,making PAAC increase their carbonyl content and the phenolic hydroxyl and aromatic primary amino content are relatively less. This provides an experimental reference and theoretical basis for further reveal the mechanism of scavenging OH and the antioxidant mechanism.更多还原