Kinetic study of the H2O2 oxidation of phenols, naphthols and anilines catalysed by the haem octapeptide microperoxidase-8

A range of phenols, naphthols and anilines has been oxidised by hydrogen peroxide using microperoxidase-8 (MP-8) as a catalyst. The rate of the reaction is independent of the nature and concentration of the substrate over a limited range, confirming that oxidation of the catalyst is the rate-limiting step. The efficiency of the catalytic oxidation, as opposed to deactivation, has been defined in terms of relative catalytic efficiency; this is dependent on the nature, but not the concentration, of the substrate. This has been interpreted as kinetic evidence for a ‘substrate involved’ MP-8 decomposition pathway.