Catalytic Models of Tyrosinase: Reactivity Differences between Systems Based on Mono‐ and Binucleating Ligands
Catalytic Models of Tyrosinase: Reactivity Differences between Systems Based on Mono‐ and Binucleating Ligands
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酪氨酸酶的催化模型：基于单核和双核配体的系统之间的反应性差异
DOI：
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
F. Tuczek
中科院分区：
文献类型：
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作者：
Julia Schottenheim;Claus Gernert;Benjamin Herzigkeit;Jan Krahmer;F. Tuczek
合成并表征了一种基于双核配体Lpy 2的酪氨酸酶模型。配体Lpy 2在侧臂中含有亚胺和吡啶官能团的组合，其通过柔性烷基间隔基桥接。如UV/维斯和NMR光谱所示，Cu 2Lpy 2络合物催化单酚2，4-二叔丁基苯酚（DTBP-H）转化为邻醌3，5-二叔丁基醌（DTBQ），转换数（TON）为18。因此，Lpy 2的双铜络合物显示出与最近开发的酪氨酸酶的Lpy 1模型相当的单酚酶活性，该模型基于已知的单核配体（M. Rolff，J. Schottenheim，G. Peters，F. Tuczek，Angew. Chem.Int.Ed.2010，122，6583）。相比之下，缺电子底物4-羟基苯甲酸甲酯（MeBA-OH）可被Cu 2Lpy 2转化为半醌。对于两种底物，氧化反应也以化学计量方式进行，以获得有关中间体的信息。对于底物MeBA-OH，我们通过高分辨率ESI质谱检测到双核μ-儿茶酚合铜（II）配合物。这些研究的补充，可以调用解释TON的局限性的失活机制的调查。为此，制备了双-μ-羟基Lpy 2二铜（II）配合物以及半醌Lpy 2配合物。这两种络合物可以代表催化剂的衰变产物。
A new tyrosinase model based on the binucleating ligand Lpy2 is synthesized and characterized. The ligand Lpy2 contains a combination of an imine and a pyridine function in the sidearms, which are bridged by a flexible alkyl spacer. As shown by UV/Vis and NMR spectroscopy, the Cu2Lpy2 complex catalyzed the conversion of the monophenol 2,4-di-tert-butylphenol (DTBP-H) into the o-quinone 3,5-di-tert-butylquinone (DTBQ) with a turnover number (TON) of 18. The dicopper complex of Lpy2 thus shows monophenolase activity that is comparable to that of the recently developed Lpy1 model of tyrosinase, which is based on a known mononucleating ligand (M. Rolff, J. Schottenheim, G. Peters, F. Tuczek, Angew. Chem. Int. Ed. 2010, 122, 6583). The electron-poor substrate 4-hydroxybenzoic acid methyl ester (MeBA-OH), in contrast, is converted by Cu2Lpy2 into the semiquinone. For both substrates, the oxygenation reactions were also conducted in a stoichiometric fashion to obtain information on the intermediates involved. For the substrate MeBA-OH, we detected a binuclear μ-catecholato copper(II) complex by high-resolution ESI mass spectrometry. These studies were complemented by investigations of deactivation mechanisms that could be invoked to explain the limitation of the TON. To this end, a bis-μ-hydroxido Lpy2 dicopper(II) complex as well as a semiquinone Lpy2 complex were prepared. Both complexes may represent decay products of the catalyst.
影响因子：
5.6
作者：
Cuff, ME;Miller, KI;Hendrickson, WA
通讯作者：
Hendrickson, WA
影响因子：
16.6
作者：
Hoffmann, Alexander;Citek, Cooper;Binder, Stephan;Goos, Arne;Ruebhausen, Michael;Troeppner, Oliver;Ivanovic-Burmazovic, Ivana;Wasinger, Erik C.;Stack, T. Daniel P.;Herres-Pawlis, Sonja
通讯作者：
Herres-Pawlis, Sonja
曲折的故事：铜（II）半醌配合物中的磁和光开关。
影响因子：
4.6
作者：
Verma,Pratik;Weir,John;Mirica,Liviu;Stack,TDanielP
通讯作者：
Stack,TDanielP