DIRECT ELECTROCHEMISTRY OF THE HYDROXYLASE OF SOLUBLE METHANE MONOOXYGENASE FROM METHYLOCOCCUS-CAPSULATUS (BATH)

The redox properties of the hydroxylase component of soluble methane m onooxygenase from Methylococcus capsulatus (Bath) have been thoroughly investigated. Previous studies used redox indicator titrations and sp ectroscopic methods for the determination of the concentrations of red uced species. Herein we report, for the first time, direct electrochem istry (i.e. without the use of mediators) of the diiron centers of the hydroxylase from M. capsulatus (Bath) at a modified gold electrode gi ving rise to two waves at 4(+/-10) mV and -386(+/-14) mV versus satura ted calomel electrode (SCE). In addition, the effects of proteins B an d B' on the redox reactions were determined. The redox potentials of t he complex with protein B are -25(+/-14) mV and -433(+/-8) mV versus S CE whereas protein B' had no effect though it did alter the effect of protein B on the redox potentials.