Structural Characterization of the Fleeting Ferric Peroxo Species in Myoglobin: Experiment and Theory

摘要

In catalytic cycles of mono-oxygenase heme enzymes, one-electron reduction of the ferrous oxy complex generates ferric peroxo (Fe~Ⅲ—OO~-). This process is often coupled with protonation of the distal peroxo oxygen through a distal pocket proton delivery system connected by a hydrogen bond to the ferrous oxy heme, resulting in formation of ferric hydroperoxo (Fe~Ⅲ—OOH). The second proton delivery to the hydroperoxo intermediate either yields an oxo ferryl porphyrin coupled with a porphyrin radical (compound I), a putative active form in P450 enzymes, or initiates hydroxylation of the heme meso-carbon in heme oxygenase (HO) without compound I formation.