Phosphorylation of acetylcholinesterase in bovine blood by Paraoxon and Soman

In order to adjust reaction conditions to physiological conditions, phosphorylation of acetylcholinesterase has been investigated, not in highly diluted erythrocyte suspensions or enzyme solutions, but in undiluted whole blood. The inhibition of esteratic activity by paraoxon within 10 to 20 min, by soman within a few minutes, reaches the final level and shows no alteration during the next hours. This deviation from a pseudo first order kinetics is caused by the enzymatic hydrolysis of paraoxon, a competitive reaction by which paraoxon is destroyed rapidly. Soman did not show this effect, evidently because of the high velocity of the phosphorylation reaction.

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