Oxidation of aromatic alcohols by laccase from Trametes versicolor mediated by the 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) cation radical and dication
Oxidation of aromatic alcohols by laccase from Trametes versicolor mediated by the 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) cation radical and dication
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DOI：
10.1007/s002530051392
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发表时间：
1999-02-01
影响因子：
5
通讯作者：
Hüttermann, A
中科院分区：
文献类型：
--
作者：
Majcherczyk, A;Johannes, C;Hüttermann, A
研究了2,2′-氮基-双-（3-乙基苯并噻唑-6-磺酸）（ABTS）的氧化产物对芳香醇（如非酚木质素模型化合物）的氧化作用。ABTS生成的阳离子自由基和阳离子化反应均能将芳香醇氧化成醛。反应终止于醛的水平，不形成酸。阳离子自由基和阳离子在氧化剂和醇之间作为电子转移化合物在一个循环中起作用。除了伯苄基羟基的氧化外，仲-羟基也可能被氧化成酮。这些反应的所有显著特征都与漆酶在ABTS存在下氧化的结果相一致。单独的分解产物和含有漆酶的ABTS的分解产物证实了其参与漆酶介质系统的假设。预测了一种以醇阳离子自由基去质子化为基础的反应机理在不可逆的后续反应中起关键作用，并成为该过程的驱动力。
Oxidation of aromatic alcohols, such as nonphenolic lignin model compounds, by oxidised species of 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) has been investigated. The cation radical and dication formed from ABTS were both capable of oxidising aromatic alcohols to aldehydes. The reactions terminated at the level of the aldehyde and no acids were formed. The cation radical and dication worked in a cycle as an electron-transfer compound between an oxidant and alcohol. In addition to the oxidation of the primary benzyl-hydroxyl group, an oxidation of the secondary alpha-hydroxyl group to the ketone by the dication was possible. All distinguishing features of these reactions corresponded to the results of the oxidation performed by the laccase of Trametes versicolor in the presence of ABTS. The decomposition products from the dication alone and ABTS with laccase confirmed the supposition that the dication was involved in the laccase mediator system. A reaction mechanism based on deprotonation of the alcohol cation radical was predicted to play a key role in the irreversible followup reaction and to be the driving force of the process.