Identification of catalytic pathways in the peroxidatic reactions of the haem octapeptide microperoxidase-8

Abstract

Reaction of microperoxidase-8 (MP-8) with H₂O₂ leads to the formation of an oxidized intermediate whose subsequent reduction by 2,4-dimethoxyphenol occurs in two stages and results in regeneration of MP-8. Analysis of the kinetics of these reactions in comparison with those of the normal peroxidatic reaction shows that at least four oxidized forms of MP-8 are capable of oxidizing the phenol. Possible structures and modes of action for these intermediates are discussed.