Oxidation reactions performed by soluble methane monooxygenase hydroxylase intermediates [H.sub.peroxo] and Q proceed by distinct mechanisms

Double-mixing stopped-flow spectroscopy was employed to study the reactions of the two intermediate species [H.sub.peroxo] and Q with a panel of substrates of varying C-H bond strength in the bacterial enzyme monooxygenase. The reaction of [H.sub.peroxo] with acetonitrile appears to proceed by a distinct mechanism in which a cyanomethide anionic intermediate is generated and provide evidence in support of [H.sub.peroxo] as an electrophilic oxidant that operates via two-electron transfer chemistry.