Phosphotriesterases mammalian

The inactivation and detoxification of paraoxon and congeners are catalyzed by the so-called A-esterases, which, as discussed, comprise aryleste-rase (sometimes still called paraoxonase, EC 3.1.1.2) and phosphoric triester hydrolases (phosphotriesterases, EC 3.1.8) subdivided into aryldialkylphos-phatase (organophosphate hydrolase, paraoxonase, EC 3.1.8.1) and organophosphorus acid anhydrolases (EC 3.1.8.2 see Sect. 9.3.7) [65][69][106-108], These activities, which occur mostly in the mammalian liver and... 

Higher rate constants of P( - )-isomers for inhibition of AChE in combination with their minor susceptibility to enzymatic hydrolysis by mammalian phosphotriesterases cause eminently different lethal doses in vivo "Benschop et al. (1984) benschop and de Jong (2001)... 

Arvlester Hydrolase and Parathion Hydrolase. Arylester hydrolase in mammalian serum (42.431 catalyzes very efficient hydrolysis of the organophosphorus oxons such as paraoxon (Table III). This enzyme does not hydrolyze the parent phosphorothioate insecticides such as methyl parathion, but only the oxon metabolites such as methyl paraoxon (441. This enzyme is has been referred to as phosphotriesterase however, a triester is not required as seen in the rapid hydrolysis of 10 organophosphinates by rabbit serum arylester hydrolase (44). This mechanism appears only rarely in birds... 

PONs (serum Mammalian lactonases EC Phosphotriesterase EC 3.I.8.X. Catalytic promiscuity 90-92... 

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