Reactions of Methane Monooxygenase Intermediate Q with Derivatized Methanes

The reactivity of intermediate Q of soluble methane monooxygenase from Methylococcus capsulatus (Bath) with a series of derivatized methanes of general formula CH3-R, where R = CN, NO2, and OH, and their deuterated analogues is described. Despite relatively slow reactions, significant kinetic isotope effects, KIEs, are observed in reactions with acetonitrile and nitromethane; however, none is obtained with methanol. In addition, evidence of a substrate-binding step that occurs prior to substrate oxidation is observed.