摘要 : Dioxygen activation by mononuclear iron oxygenases in general requires two electrons and protons to facilitate reductive cleavage of the O-O bond and formation of a high-valent iron oxidant.For enzymes with an iron(III)resting sta... 展开 Dioxygen activation by mononuclear iron oxygenases in general requires two electrons and protons to facilitate reductive cleavage of the O-O bond and formation of a high-valent iron oxidant.For enzymes with an iron(III)resting state,the oxidant is postulated to have a formally Fe~V oxidation state,for example,Fe~(IV)(O)(porphyrin radical)for cytochrome P450 and Fe~V(O)(OH)for the Rieske dioxyge-nases.On the other hand,enzymes with an iron(II)resting state often require a tetrahydropterin or an alpha-keto acid cofactor to form an Fe~(IV)(O)intermediate.Such intermediates have recently been trapped and characterized for several enzymes. 收起