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首页> 外文期刊>Chemistry: A European journal >Galactose Oxidase Models:Solution Chemistry,and Phenoxyl Radical Generation Mediated by the Copper Status
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Galactose Oxidase Models:Solution Chemistry,and Phenoxyl Radical Generation Mediated by the Copper Status

机译：半乳糖氧化酶模型：溶液化学和铜状态介导的苯氧基自由基生成

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Galactose oxidase(GO)is an enzyme that catalyzes two-electron oxidations.Its active site contains a copper atom coordinated to a tyrosyl radical,the biogenesis of which requires copper and dioxygen.We have recently studied the properties of elec-trochemically generated mononuclear Cu~II-phenoxyl radical systems as model compounds of GO.We present here the solution chemistry of these ligands under various copper and dioxygen statuses:N_3O ligands first chelate Cu~II,leading,in the presence of base,to [Ca~IIligand](CH_3CN)]~+ complexes(ortfzo-tert-butylated ligands)or [(Cu~II)_2(ligand)_2]~(2+)complexes(ortho-methoxylated ligands).Excess copper-(II)then oxidizes the complex to the corresponding mononuclear Cu~II-phenoxyl radical species.N_2O_2 tripodal ligands,in the presence of copper(II),afford directly a copper(II)-phenoxyl radical species.Addition of more than two molar equivalents of copper(II)affords a Cu~II-bis(phenoxyl)diradical species.The donor set of the ligand directs the reaction towards comproportionation for ligands possessing an N_3O donor set,while disproportionate is observed for ligands possessing an N_2O_2 donor set.These results are discussed in the light of recent results concerning the self-processing of GO.A path involving copper(II)disproportionation is proposed for oxidation of the cross-linked tyrosinate of GO,supporting the fact that both copper(I)and copper(II)activate the enzyme.
机译：半乳糖氧化酶（GO）是一种催化两电子氧化的酶，其活性位点包含一个与酪氨酰自由基配位的铜原子，其生物发生需要铜和双氧。我们最近研究了电化学生成的单核铜的性质。 〜II-苯氧基自由基体系作为GO的模型化合物。在此，我们介绍这些配体在各种铜和双氧状态下的溶液化学：N_3O配体首先与Cu〜II螯合，导致在碱存在下成为[Ca〜II配体] （CH_3CN）]〜+络合物（叔丁基叔丁基化的配体）或[（Cu〜II）_2（配体）_2]〜（2+）络合物（邻甲氧基化的配体）。过量的铜-（II）然后氧化与相应的单核Cu〜II-苯氧基自由基物种形成络合物.N_2O_2三脚架配体在铜（II）存在下直接提供铜（II）-苯氧基自由基物种。添加两个摩尔当量以上的铜（II）生成Cu〜II-双（苯氧基）双自由基物种。配体的供体组指导区域具有N_3O供体组的配体的配位关系，而具有N_2O_2供体组的配体的配位不均衡，结合GO自处理的最新结果讨论了这些结果。涉及铜（II）歧化的路径是提出用于氧化GO的交联酪氨酸盐的方法，支持了铜（I）和铜（II）均激活该酶的事实。

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