漆酶催化邻苯二酚开环的自由基反应机制（英文）

发布时间：2018-03-24 17:48

本文选题：漆酶　切入点：自由基氧化　出处：《物理化学学报》2017年03期

【摘要】：酶催化反应是绿色化学领域中的研究热点之一。在常用的酶中,漆酶是一种多铜氧化酶。在此,漆酶被用来研究邻苯二酚的氧化和芳香环开环的自由基过程。实验表明,邻苯二酚的初始氧化产物是一个半醌自由基,再发生分子间加成反应而生成二聚体和三聚体(通过质谱鉴定),和分子内加成而生成可被5,5-二甲基-1-氧化吡咯啉(DMPO)所捕获的含有支链烷基自由基的呋喃衍生物。后者经核磁共振氢谱(~1H-NMR)加以分析。同时,通过~(17)O同位素标记追踪方法,我们发现水直接参与该分子内加成反应,并释放出~(17)O标记的羟基自由基(?~(17)OH)。此外,除了3-甲基邻苯二酚和4-甲基邻苯二酚两种类似物,此自由基过程在间苯二酚、对苯二酚、萘二酚、3-硝基邻苯二酚和4-硝基邻苯二酚等底物中均未发生。据此,我们对C_4-C_5位点的选择性活化与开环的机理展开分析和讨论,并将该机理与邻苯二酚双加氧酶导致的邻苯二酚双氧中间位置和相邻位置的开环过程相比较。这些结果将有益于漆酶的改造和仿生。
[Abstract]:Enzyme catalytic reaction is one of the hot research in the field of green chemistry. In common enzymes, laccase is a multicopper oxidase. The laccase was used to study the process of free radical oxidation of catechol and aromatic ring opening. Experimental results show that the initial oxidation products of catechol semiquinone free radical is 1.5, then the occurrence of intermolecular the addition reaction generated two dimer and trimer (by mass spectrometry), and intramolecular addition generated by 5,5- two oxidation of methyl -1- pyrrolidine (DMPO) containing branched alkyl radicals of furan derivatives captured by the latter. Nuclear magnetic resonance spectroscopy (~1H-NMR) analysis. At the same time, through. (17) O isotope tracing method, we found the water directly involved in the intramolecular cycloaddition reaction and release of ~ (17) O labeled hydroxyl radical (? ~ (17) OH). In addition, in addition to 3- methylcalechol and 4- methylcalechol two analogues This process, free radicals in resorcinol, hydroquinone, phenol and naphthalene two, 3- nitro catechol and 4- nitro catechol as the substrate did not occur. Therefore, we are selective for C_4-C_5 locus activation and open loop mechanism analysis and discussion, and the open loop mechanism and process of the catechol dioxygenase to catechol dioxygen the middle position and the adjacent position is compared. The transformation and these results will be beneficial to the bionic laccase.

【作者单位】：中国科学技术大学近代物理系中国科学院微观磁共振重点实验室;安徽大学生命科学学院生物制造创意中心;
【基金】：supported by the National Key Basic Research Program of China(973)(2013CB921802) Fundamental Research Funds for the Central Universities,China,State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources,China(KSL-CUSAb-2012-03)~~
【分类号】：O621.251

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