Formation of an End-On Ferric Peroxo Intermediate upon One-Electron Reduction of a Ferric Superoxo Heme
Formation of an End-On Ferric Peroxo Intermediate upon One-Electron Reduction of a Ferric Superoxo Heme
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DOI：
10.1021/ja1001955
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发表时间：
2010-03-24
影响因子：
15
通讯作者：
Naruta, Yoshinori
中科院分区：
文献类型：
--
作者：
Liu, Jin-Gang;Shimizu, Yuta;Naruta, Yoshinori
低自旋末端的过氧血红素铁中间体被认为是参与一氧化氮合酶和细胞色素P450等酶催化循环的一种替代反应中间体。这种瞬时的血红素中间体从未使用合成的血红素模型捕捉到。在这里，我们展示了我们成功地制备了这样一个来自血红素模型的末端过氧铁中间体，它的特征是一个基团悬挂在卟啉大环上，并通过其铁超氧前驱体的单电子还原来连接一个共价的轴向咪唑配体。得到的过氧铁中间体在质子化后进一步转化为相应的氢过氧铁物种。这种血红素模型化合物提供了一个方便的体系，通过类似于酶系统使用的机理的氧化/单电子还原/质子化过程，连续制备重要的和生物相关的超氧/过氧/氢过氧血红素中间体。
The low-spin end-on ferric peroxo heme intermediate has been proposed as an alternative reactive intermediate involved in the catalytic cycles of enzymes Such as nitric oxide synthase and cytochrome P450. This transient heme intermediate has never been captured using synthetic heme models. We demonstrate herein Our Success in the Solution preparation of Such an end-on ferric peroxo intermediate derived from a heme model, which features both a group hanging Over the porphyrin macrocycle and a covalently appended axial imidazole ligand, through one-electron reduction of its ferric superoxo precursor. The obtained ferric peroxo intermediate was further transformed into the corresponding ferric hydroperoxo species upon protonation. This heme model compound provides a convenient system for sequential preparation of the important and biologically relevant superoxo/peroxo/hydroperoxo heme intermediates through an oxygenation/one-electron reduction/protonation process similar to the mechanisms used by enzyme systems.