title: Kinetics of the DFPase activity in Tetrahymena thermophila.
abstract: Crude homogenates of the ciliate protozoon, Tetrahymena thermophila, can hydrolyze the potent acetylcholinesterase inhibitors O,O-diisopropylphosphorofluoridate (DFP) and O-1,2,2-trimethylpropylmethylphosphonofluoride (soman). Characterization of the enzymatic activity of the homogenate has been performed. The DFPase operates over a pH range of 4 to 10 and an ionic range of 0-500 mM NaCl. Rate of reaction increases three- to four-fold from 25 degrees C to 40 degrees C and is still present at 55 degrees C. These results indicate that the enzymatic activity operates over a broad range of environmental conditions, making it an attractive material for use in the detoxification and detection of organofluorophosphates. DFPases may be important in the metabolism of naturally occurring organophosphates.
mesh_terms: D000818:Animals; D004950:Esterases; D006863:Hydrogen-Ion Concentration; D006867:Hydrolases / Q000378:metabolism*; D007531:Isoflurophate / Q000378:metabolism; D007700:Kinetics; D044345:Phosphoric Triester Hydrolases; D012999:Soman / Q000378:metabolism; D013696:Temperature; D013768:Tetrahymena / Q000201:enzymology*
chemical_list: D007531:Isoflurophate; D012999:Soman; D006867:Hydrolases; D004950:Esterases; D044345:Phosphoric Triester Hydrolases; C020061:diisopropyl-fluorophosphatase