title: Heme-(hydro)peroxide mediated O- and N-dealkylation. A study with microperoxidase.
abstract: The mechanism of microperoxidase-8 (MP-8) mediated O- and N-dealkylation was investigated. In the absence of ascorbate (peroxidase mode), many unidentified polymeric products are formed and the extent of substrate degradation correlates (r = 0.94) with the calculated substrate ionization potential, reflecting the formation of radical intermediates. In the presence of ascorbate (P450 mode) formation of polymeric products is largely prevented but, surprisingly, dealkylation is not affected. In addition, aromatic hydroxylation and oxidative dehalogenation is observed. The results exclude a radical mechanism and indicate the involvement of a (hydro)peroxo-iron heme intermediate in P450-type of heteroatom dealkylation.
authors.affiliation: Laboratory of Biochemistry and Division of Toxicology,Wageningen University, The Netherlands.
authors.forename: M G
authors.initials: MG
authors.lastname: Boersma
authors.forename: J L
authors.initials: JL
authors.lastname: Primus
authors.forename: J
authors.initials: J
authors.lastname: Koerts
authors.forename: C
authors.initials: C
authors.lastname: Veeger
authors.forename: I M
authors.initials: IM
authors.lastname: Rietjens
mesh_terms: D000478:Alkylation; D000814:Aniline Compounds / Q000737:chemistry / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D006418:Heme / Q000737:chemistry* / Q000378:metabolism*; D010544:Peroxidases / Q000378:metabolism*; D010545:Peroxides / Q000737:chemistry* / Q000378:metabolism*; D011789:Quantum Theory; D013379:Substrate Specificity
chemical_list: D000814:Aniline Compounds; D010545:Peroxides; D006418:Heme; D003577:Cytochrome P-450 Enzyme System; D010544:Peroxidases; C021799:microperoxidase