title: Stereo-specific degradation of the R-(+) isomer of O-n-hexyl-S-methylphosphorothioamidate catalysed by rabbit serum.
abstract: Resolved isomers of O-n-hexyl-S-methylphosphorothioamidate (HXM) which had been synthesised by separate stereospecific routes were analysed by chiral glc: about 2-3% of R-(+) isomer was found in the S-(-) sample and accounted for nearly all the inhibitory power against neuropathy target esterase. Incubation of racemic HXM with rabbit serum led to slow but very specific disposal of R-(+) isomer to undetectable levels with very slight loss of S-(-): the rate of disposal was roughly estimated to be about 1% of the published rate of hydrolysis of paraoxon. Incubation with crystalline chymotrypsin caused a preferential but not totally selective disposal of S-(-) isomer.
authors.affiliation: MRC Toxicology Unit, University of Leicester, UK.
authors.forename: M K
authors.initials: MK
authors.lastname: Johnson
authors.forename: D J
authors.initials: DJ
authors.lastname: Read
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology; D002265:Carboxylic Ester Hydrolases / Q000037:antagonists & inhibitors / Q000097:blood; D002384:Catalysis; D002645:Chickens; D002800:Cholinesterase Inhibitors / Q000097:blood* / Q000302:isolation & purification; D002849:Chromatography, Gas; D005260:Female; D009946:Organothiophosphorus Compounds / Q000097:blood* / Q000302:isolation & purification; D011817:Rabbits; D013237:Stereoisomerism
chemical_list: D002800:Cholinesterase Inhibitors; D009946:Organothiophosphorus Compounds; C082480:O-n-hexyl-S-methylphosphorothioamidate; D002265:Carboxylic Ester Hydrolases; C021859:neurotoxic esterase