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Halide Activation by Heme Peroxidases: Theoretical Predictions on Putative Adducts of Halides with Compound I
Author(s) -
SilaghiDumitrescu Radu
Publication year - 2008
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200800732
Subject(s) - chemistry , adduct , halide , ferric , heme , moiety , ligand (biochemistry) , halogen , covalent bond , stereochemistry , myeloperoxidase , peroxidase , hemeprotein , reactivity (psychology) , medicinal chemistry , photochemistry , organic chemistry , enzyme , medicine , pathology , inflammation , biochemistry , alkyl , receptor , alternative medicine
The first density functional theory (DFT) results on models of the putative Fe III –OX and Fe III –HOX (X = halogen) adducts of chloroperoxidase (CPO) and myeloperoxidase (MPO) are reported, and their stability and electronic structure assessed. The oxygen–halogen bonds are computed to be particularly weak, to the extent where ferric hypohalous acid complexes with intact oxygen–halide bonds should be difficult to observe in heme peroxidases; a ‘caged' adduct, featuring a ferric species in close (but not covalent) contact with the oxidized halide, appears as a likely alternative for an observable intermediate in CPO and MPO. The presence of an axial thiolate (CPO) or imidazole (MPO) ligand in a position trans to the hypohalous moiety is calculated to have a distinct effect on halide activation, with relevance to the TSR (two‐state reactivity) concept.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)