NOTES ON THE DECOMPOSITION OF PARATHION IN LIVING OPGANISMS : Ⅲ. SERUM PARATHION SPLITTING ACTIVITY AND SERUM ALKALINE PHOSPHATASE

The variation of serum parathion-splitting activity and serum alkaline phosphatese in the dogs poisoned with varied amounts of parathion and KDTP was studies to examine the similarity of those enzymes. Their inhibitors and activators were compared for the same purpose. The following are the conclusions: 1. Serum parathion-splitting substance is not identical with serum alkaline phosphatase. Both have the the same optimum range of pH, but in the former is not inactivated by fluoride which is a potent inhibitor to the latter. The parathionsplitting activity is not affected and remains rather constant in parathion-poisoned dogs presenting a distinct contrast to serum alkaline phosphatase which shows a considerable increase unber the same condition. 2. Serum parathion-splitting substance is neither identical with cholinesterase nor A esterase. Their behavior in parathion or KDTP poisoning, optimum pH, inhibitors and activators are different. 3. There is a rise in serum alkaline phosphatase activity in the dogs injected with parathion or KDTP. Deduction is made that diethylthiophsphate which is a partial degradation product os those druogs stimulates the tissues to produce in creased amounts of alkaline phosphatase.