Revisiting the mechanism of dioxygen activation in soluble methane monooxygenase from M. capsulatus (Bath): evidence for a multi-step, proton-dependent reaction pathway.

ABSTRACT: Stopped-flow kinetic investigations of soluble methane monooxygenase (sMMO) from M. capsulatus (Bath) have clarified discrepancies that exist in the literature regarding several aspects of catalysis by this enzyme. The development of thorough kinetic analytical techniques has led to the discovery of two novel oxygenated iron species that accumulate in addition to the well-established intermediates H(peroxo) and Q. The first intermediate, P*, is a precursor to H(peroxo) and was identified when the reaction of reduced MMOH and MMOB with O(2) was carried out in the presence of >or=540 microM methane to suppress the dominating absorbance signal due to Q. The optical properties of P* are similar to those of H(peroxo), with epsilon(420) = 3500 M(-1) cm(-1) and epsilon(720) = 1250 M(-1) cm(-1). T

SUBMITTER: Tinberg CE 

PROVIDER: S-EPMC2797563 | biostudies-literature | 2009 Dec

REPOSITORIES: biostudies-literature