title: Influence of organophosphorus pesticides on peroxidase and chlorination activity of human myeloperoxidase.
abstract: Inhibitory effects of five organophosphorus pesticides (diazinon, malathion, chlorpyrifos, azinphos-methyl and phorate) and their oxo-analogs on human myeloperoxidase (MPO) activity were investigated. While inspecting separately peroxidase and chlorination activity, it was observed that investigated OPs affect peroxidase activity, but not chlorination activity. Among investigated pesticides, malathion and malaoxon have showed the highest power to inhibit MPO peroxidase activity with IC50 values of the order of 3×10(-7) and 5×10(-9) M, respectively. It was proposed that inhibition trend is rendered by molecular structure which invokes steric hindrance for OPs interaction with MPO active center responsible for peroxidase activity. In addition, it was concluded that physiological function of MPO is not affected by any of the investigated OPs.
authors.affiliation: Department of Physical Chemistry, Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia. Electronic address: tamara@vinca.rs.
authors.forename: Tamara
authors.initials: T
authors.lastname: Lazarević-Pašti
authors.affiliation: Department of Physical Chemistry, Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia.
authors.forename: Tatjana
authors.initials: T
authors.lastname: Momić
authors.affiliation: University of Belgrade, School of Medicine, Dr. Subotica 8, 11000 Belgrade, Serbia.
authors.forename: Miloš M
authors.initials: MM
authors.lastname: Radojević
authors.affiliation: Department of Physical Chemistry, Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia.
authors.forename: Vesna
authors.initials: V
authors.lastname: Vasić
mesh_terms: D054879:Halogenation / Q000187:drug effects; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007306:Insecticides / Q000494:pharmacology*; D009943:Organophosphorus Compounds / Q000494:pharmacology*; D009195:Peroxidase / Q000378:metabolism*
chemical_list: D007306:Insecticides; D009943:Organophosphorus Compounds; D006861:Hydrogen Peroxide; D009195:Peroxidase
keywords: Inhibition; Malathion; Myeloperoxidase; Organophosphate; Pesticide