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酚氧自由基化木质素的可能降解途径探究

发表时间:2019-08-30  浏览量:184  下载量:13
全部作者: 王源祺,康锴,郑光辉,张海军,赵一雷
作者单位: 上海交通大学生命科学技术学院,微生物代谢国家重点实验室
摘 要: 木质素是一种在植物中广泛存在的生物高聚物,其中酚羟基可以在漆酶的作用下转化为酚氧自由基,但被漆酶激活后的酚氧自由基化木质素的下游生物化学机制尚不清楚。本文分析了酚氧自由基化木质素的ReaxFF模拟轨迹,统计其中各类化学键的变化规律。结果表明,愈创木基3-O醚键、β-O-4醚键、α-O-4醚键及4-O-5醚键具有较明显的延长倾向。进一步通过量子力学密度泛函方法(U)B3LYP/6-311+G(d,p)//6-31G(d)计算了可能降解途径的反应焓和活化能,提出了双酚氧自由基反应可能是漆酶引发木质素降解的主要途径。
关 键 词: 生物化学;木质素;ReaxFF;自由基;量子化学;计算化学
Title: Exploration of possible degradation pathway of phenoxy-radical lignin
Author: WANG Yuanqi, KANG Kai, ZHENG Guanghui, ZHANG Haijun, ZHAO Yilei
Organization: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University
Abstract: Lignin is a type of biopolymer that widely exists in plant, and its phenol substitution can be transformed to phenoxy radicals under laccase’s catalysis. However, its following-up biochemical pathway remains unknown. In this work, we have analyzed the trajectories of phenoxy-radical lignin generated with the ReaxFF, and statistically explored variations in each type of chemical bond. As a result, guaiacyl 3-O ether bonds, β-O-4 ether bonds, α-O-4 ether bonds and 4-O-5 ether bonds exhibited a relatively high tendency in bond elongation. We further calculated the reaction enthalpy and activation energy of the possible degradations with the quantum mechanics density functional theory at the level of (U)B3LYP/6-311+G(d,p)//6-31G(d). It is suggested that diphenoxy-radical pathway might be essential for laccase-initiated lignin decomposition.
Key words: biochemistry; lignin; ReaxFF; free radical; quantum chemistry; computational chemistry
发表期数: 2019年8月第4期
引用格式: 王源祺,康锴,郑光辉,等. 酚氧自由基化木质素的可能降解途径探究[J]. 中国科技论文在线精品论文,2019,12(4):638-648.
 
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