酚类污染物与L-Cys间的作用机理和电子传递

Mechanism of Interaction and Electron Transfer Between Phenolic Pollutants and L-Cysteine

采用电化学循环伏安法和紫外吸收光谱方法,研究了L-半胱氨酸(L-Cys)与苯二酚污染物之间相互结合的作用机理和电子传递信息.结果表明:固定在金表面、排列呈有序结构的单分子层膜状态的L-半胱氨酸与苯二酚相互作用时,对三种苯二酚异构体的氧化还原反应均有良好的电催化作用,有利于电子转移过程的发生;而分散游离于水溶液中、呈无序游离结构状态的L-半胱氨酸与苯二酚相互作用时,对氧化还原反应起阻碍作用,不利于电子转移.进一步研究表明,二者之间的相互作用不涉及化学键强作用力,未发生分子化学键的断裂和新键的形成.半胱氨酸与苯二酚污染物通过N…H—O氢键,结合形成L-Cys.C6H6O2或(L-Cys)2.C6H6O2缔合物.分子间结合点数目的不同,导致其电化学活性和行为的差异,并使生物分子的功能发生变异.

The mechanism of interaction between L-Cysteine and phenolic pollutants was investigated on the basis of cyclic voltammetry and the UV-Vis spectrophotometry methods. Results show that L-Cysteine immobilized onto Au electrode with orderly arranged monolayer membrane can facilitate electrons transfer and electrocatalyze the redox of the three dihydric phenols but affect the redox of the three dihydric phenols and electrons transfer when dispersed in aqueous solution and presented in free and disorderly structure. Further research indicates that no strong chemical action occurs between L-Cysteine and dihydric phenols, nor does cleavage of old chemical bonds or formation of new bonds. L-Cysteine and dihydric phenols can form L-Cys·C6H6O2 or （ L-Cys）2·C6H6O2 through hydrogenbonding association. The difference in binding number results in different electrochemical activity and behavior, and also leads to different biomolecular function.