Kovaleva Elena G, Lipscomb John D
Department of Biochemistry, Molecular Biology and Biophysics and the Center for Metals in Biocatalysis, University of Minnesota, 6-155 Jackson Hall, Minneapolis, Minnesota 55455, USA.
Nat Chem Biol. 2008 Mar;4(3):186-93. doi: 10.1038/nchembio.71.
Oxidase and oxygenase enzymes allow the use of relatively unreactive O2 in biochemical reactions. Many of the mechanistic strategies used in nature for this key reaction are represented within the 2-histidine-1-carboxylate facial triad family of non-heme Fe(II)-containing enzymes. The open face of the metal coordination sphere opposite the three endogenous ligands participates directly in the reaction chemistry. Here, data from several studies are presented showing that reductive O2 activation within this family is initiated by substrate (and in some cases cosubstrate or cofactor) binding, which then allows coordination of O2 to the metal. From this starting point, the O2 activation process and the reactions with substrates diverge broadly. The reactive species formed in these reactions have been proposed to encompass four oxidation states of iron and all forms of reduced O2 as well as several of the reactive oxygen species that derive from O-O bond cleavage.
氧化酶和加氧酶能使相对不活泼的O₂用于生化反应。自然界中用于这一关键反应的许多机制策略都体现在含非血红素Fe(II)的2-组氨酸-1-羧酸盐面三联体家族酶中。与三个内源性配体相对的金属配位球的开放面直接参与反应化学过程。在此，给出了几项研究的数据，表明该家族内的还原性O₂活化是由底物（在某些情况下是共底物或辅因子）结合引发的，这随后使得O₂能与金属配位。从这一起点开始，O₂活化过程以及与底物的反应有很大差异。这些反应中形成的活性物种被认为包括铁的四种氧化态、所有形式的还原态O₂以及几种由O-O键断裂产生的活性氧物种。
