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首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >Transient species involved in catalytic dioxygen/peroxide activation by hemoproteins:possible involvement of protonated Compound I species
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Transient species involved in catalytic dioxygen/peroxide activation by hemoproteins:possible involvement of protonated Compound I species

机译：涉及血红素催化双氧/过氧化物活化的瞬态物种：质子化化合物I物种可能参与

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Interaction of hemoproteins with peroxide leads in several cases to transient formation of ferric peroxo,ferric hydroperoxo,and "high-valent",formally Fe(v),oxo or hydroxo Compound I species.Here,density functional calculations on ferric peroxo,ferric hydroperoxo,Compound I and protonated Compound I heme active site models are reported.The theoretical results,including calculated isotropic Fermi contact couplings and anisotropic spin dipole couplings,are found to generally correlate well with experimental EPR/ENDOR data.Hydrogen bonding and solvation affect the ferric-peroxo/ferrous-superoxo electromerism.The transition between the two electromers appears smooth,but neither hydrogen bonding to up to two water molecules,nor solvation appear able to dramatically alter the redox state of the superoxo ligand or of the iron.The presence of almost one full unpaired electron on the iron and of one full unpaired electron on the dioxygenic ligand in the "ferric-peroxo" state suggests a possible description of non-protonated "ferric-peroxo" as {ferric-superoxo+porphyrin radical}.Emerging from the DFT data is the possibility that a protonated Compound I has already been detected in ENDOR experiments on cytochrome P450.The general feasibility of a protonated Compound I in P450 monooxygenases is probed in light of these findings.To encompass the multiple mechanisms available in P450 for substrate oxidation,we define "mechanistic promiscuity" as the feature allowing an enzyme to perform the same reaction,with the same product,using more than one mechanism.
机译：血蛋白与过氧化物的相互作用在某些情况下会导致瞬时形成铁过氧化物，铁氢过氧化物和“高价”形式的Fe（v），氧或氢氧化合物I物种。在此，关于铁过氧，铁氢过氧化物的密度泛函计算报道了化合物I和质子化的化合物I血红素活性位点模型。发现理论结果，包括计算的各向同性费米接触耦合和各向异性自旋偶极偶合，通常与实验EPR / ENDOR数据良好相关。氢键和溶剂化影响三价-过氧/亚铁-超氧介电异构体。两种电子异构体之间的过渡看起来很平滑，但氢键最多与两个水分子键合，也没有溶剂化作用，无法显着改变超氧羰基或铁的氧化还原态。铁上几乎有一个完全不成对的电子，双氧合配体上有一个完全不成对的电子处于“铁-过氧”状态，表明可能非质子化的“铁-过氧”描述为{铁-超氧+卟啉基}。从DFT数据中得出的可能性是，在细胞色素P450的ENDOR实验中已检测到质子化的化合物I。质子化的一般可行性根据这些发现，对P450单加氧酶中的化合物I进行了研究。为涵盖P450中可用于底物氧化的多种机制，我们将“机械混杂”定义为允许酶与相同产物进行相同反应，使用更多产物的特征。不止一种机制。

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