Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1925847 | Archives of Biochemistry and Biophysics | 2011 | 11 Pages |
The mechanism of the dehalogenation step catalyzed by dehaloperoxidase (DHP) from Amphitrite ornata, an unusual heme-containing protein with a globin fold and peroxidase activity, has remarkable similarity with that of the classical heme peroxidase, horseradish peroxidase (HRP). Based on quantum mechanical/molecular mechanical (QM/MM) modeling and experimentally determined chlorine kinetic isotope effects, we have concluded that two sequential one electron oxidations of the halogenated phenol substrate leads to a cationic intermediate that strongly resembles a Meisenheimer intermediate – a commonly formed reactive complex during nucleophilic aromatic substitution reactions especially in the case of arenes carrying electron withdrawing groups.
Research highlights► HRP and DHP catalyze dehalogenation reaction at an external site. ► Dehalogenation act catalyzed by HRP and DHP proceeds via cationic intermediate. ► Dehalogenation step is not rate limiting.