title: Interaction of halides with the cyanide complex of myeloperoxidase: a model for substrate binding to compound I.
abstract: EPR spectra of the low-spin cyanide complex of myeloperoxidase have been measured in the absence and presence of halide substrates; chloride, bromide and iodide. Halide-dependent spectral changes are found at acidic pH. The electronic structure of the low-spin ferric iron in cyanide complex appears to be modulated by halide binding to a protonated amino acid in the distal heme cavity. These findings suggest halide substrates can interact with ferryl oxygen in compound I during enzyme catalysis to form hypohalous acid.
authors.affiliation: Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia.
authors.forename: H C
authors.initials: HC
authors.lastname: Lee
authors.forename: K S
authors.initials: KS
authors.lastname: Booth
authors.forename: W S
authors.initials: WS
authors.lastname: Caughey
authors.forename: M
authors.initials: M
authors.lastname: Ikeda-Saito
mesh_terms: D001965:Bromides / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism*; D003486:Cyanides / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D007454:Iodides / Q000378:metabolism*; D007700:Kinetics; D009195:Peroxidase / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation
chemical_list: D001965:Bromides; D002712:Chlorides; D003486:Cyanides; D007454:Iodides; D009195:Peroxidase