NOTES ON THE DECOMPOSITION OF PARATHION IN LIVING ORGANISMS : Ⅰ. PARATION-SPLITTING ACTIVITY OF BLOOD SERUM AND SERUM CHOLINESTERASE

1, An enzyme-like substance has been discovered in the canine blood serum which parathion ( diethyl p-nitrophenylthiophosphate ). 2, This substance is not identical with the serum cholinesterase. The parathionsplitting activity of the serum remained unchanged in dogs following an injection of parathion in emulsion, neither was there any correlation between the serum parathion-splitting activity and the urinary p-nitrophenol. 3, Potassium diethylthiophosphate did not interfere with the serum cholinesterase activity, and therefore may be a nontoxic substance.