Differentiation of esterases reacting with organophosphorus compounds.
The hydrolysis of paraoxon (POX), phenylacetate (PA) and beta-naphthylacetate (BNA) was studied in human serum. Based upon correlations between enzyme activities, upon reversible inhibition by EDTA and upon progressive inhibition by iso-OMPA, tabun, eserine and bis-4 nitrophenylphosphate, the following conclusions were drawn about the number and specificity of enzymes involved in the hydrolysis. Two paraxonases hydrolyse paraoxon: one sensitive and the other insensitive to EDTA. The EDTA-sensitive paraoxonase also hydrolysed BNA. The EDTA-insensitive hydrolysis of BNA and PA was attributed to a serine esterase. The EDTA-sensitive hydrolysis of PA is probably due to more than one enzyme, which might be an arylesterase and a carboxylesterase.
Reiner
E
E
Institute for Medical Research and Occupational Health, University of Zagreb, Croatia.
Pavković
E
E
Radić
Z
Z
Simeon
V
V
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D043303:Aryldialkylphosphatase; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D002802:Cholinesterases / Q000378:metabolism; D004492:Edetic Acid / Q000494:pharmacology; D004950:Esterases / Q000037:antagonists & inhibitors / Q000097:blood* / Q000145:classification; D005260:Female; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D009280:Naphthaleneacetic Acids / Q000378:metabolism; D009596:Nitrophenols / Q000494:pharmacology; D010755:Organophosphates / Q000494:pharmacology; D009943:Organophosphorus Compounds / Q000097:blood / Q000378:metabolism*; D010261:Paraoxon / Q000378:metabolism; D010648:Phenylacetates / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010830:Physostigmine / Q000494:pharmacology; D012680:Sensitivity and Specificity; D013379:Substrate Specificity; D013770:Tetraisopropylpyrophosphamide / Q000494:pharmacology; D013860:Thiocholine / Q000031:analogs & derivatives / Q000378:metabolism
D002800:Cholinesterase Inhibitors; D009280:Naphthaleneacetic Acids; D009596:Nitrophenols; D010755:Organophosphates; D009943:Organophosphorus Compounds; D010648:Phenylacetates; C009063:propionylthiocholine; D013770:Tetraisopropylpyrophosphamide; C020424:2-naphthylacetic acid; D013860:Thiocholine; C002887:bis(4-nitrophenyl)phosphate; D004492:Edetic Acid; D010830:Physostigmine; D004950:Esterases; D002802:Cholinesterases; D010744:Phosphoric Monoester Hydrolases; D043303:Aryldialkylphosphatase; C025136:phenylacetic acid; D010261:Paraoxon; C009374:tabun