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High-valent iron in chemical and biological oxidations
被引:502
作者:
Groves, John T.
[1
]
机构:
[1] Princeton Univ, Dept Chem, Princeton, NJ 08544 USA
关键词:
cytochrome P450;
chloroperoxidase;
AlkB;
sMMO;
oxygen rebound;
ferryl;
Fenton;
mechanism;
D O I:
10.1016/j.jinorgbio.2006.01.012
中图分类号:
Q5 [生物化学];
Q7 [分子生物学];
学科分类号:
071010 ;
081704 ;
摘要:
Various aspects of the reactivity of iron(IV) in chemical and biological systems are reviewed. Accumulated evidence shows that the ferryl species [Fe(IV)=O](2+) can be formed under a variety of conditions including those related to the ferrous ion-hydrogen peroxide system known as Fenton's reagent. Early evidence that such a species could hydroxylate typical aliphatic C-H bonds included regioselectivities and stereospecificities for cyclohexanol hydroxylation that could not be accounted for by a freely diffusing hydroxyl radical. Iron(lV) porphyrin complexes are also found in the catalytic cycles of cytochrome P450 and chloroperoxidase. Model oxo-iron(IV) porphyrin complexes have shown reactivity similar to the proposed enzymatic intermediates. Mechanistic studies using mechanistically diagnostic substrates have implicated a radical rebound scenario for aliphatic hydroxylation by cytochrome P450. Likewise, several non-heme diiron hydroxylases, AlkB (Q-hydroxylase), sMMO (soluble methane monooxygenase), XyIM (xylene monooxygenase) and T4moH (toluene monooxygenase) all show clear indications of radical rearranged products indicating that the oxygen rebound pathway is a ubiquitous mechanism for hydrocarbon oxygenation by both heme and non-heme iron enzymes. (c) 2006 Elsevier Inc. All rights reserved.
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页码:434 / 447
页数:14
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