title: Organophosphate detoxicating hydrolases in different vertebrate species.
abstract: Phosphorylphosphatase activities in various organs of vertebrate species from different classes were determined using a spectrophotometric assay for paraoxonase (EC 3.1.1.2) and a potentiometric assay with a fluoride sensitive electrode for DFPase (EC 3.8.2.1). Temperature-dependent inactivation experiments, an extended interpretation of mixed substrate studies and activity distribution patterns confirm that in vertebrate tissue at least two different enzymes are responsible for hydrolytic detoxication of paraoxon and DFP. Total organophosphate detoxicating phosphorylphosphatase activity of a certain animal species is shown to be the major determinant for differences between the inhibitory potency of organophosphorus compounds on the animal's target enzymes in vitro and organophosphate toxicity in vivo.
mesh_terms: D000818:Animals; D043303:Aryldialkylphosphatase; D002417:Cattle; D002645:Chickens; D004950:Esterases; D005399:Fishes; D006867:Hydrolases / Q000378:metabolism*; D008658:Inactivation, Metabolic; D007700:Kinetics; D008253:Macaca mulatta; D009943:Organophosphorus Compounds / Q000378:metabolism*; D010261:Paraoxon / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D044345:Phosphoric Triester Hydrolases; D011817:Rabbits; D013045:Species Specificity; D013552:Swine; D014018:Tissue Distribution
chemical_list: D009943:Organophosphorus Compounds; D006867:Hydrolases; D004950:Esterases; D010744:Phosphoric Monoester Hydrolases; D044345:Phosphoric Triester Hydrolases; D043303:Aryldialkylphosphatase; C020061:diisopropyl-fluorophosphatase; D010261:Paraoxon