BIOACTIVATION OF ISOFENPHOS CHIRAL ISOMERS (O-ETHYL O-2-ISOPROPOXYCARBONYLPHENYL N-ISOPROPYLPHOSPHORAMIDOTHIOATE)

摘要

Isofenphos was the most toxic to the adzuki bean weevil among N-alkyl substituted phosphoramidothioates tested and fenitrothion. The LD_(50) value of isofenphos was not correlated with in vitro anti-acetylcholinesterase (AChE) activity of isofenphos-oxon. I_(50) values of isofenphos-oxon for AChE derived from adzuki bean weevil and bovine serum was strongly inhibited in the presence of NADPH, and SKF 525-A reduced the inhibition of AChE activity. The compounds also became potent inhibition of AChE by chemical treatment with m-chloroperbenzoic acid. It was concluded that isofenphos and isofenphos-oxon were activated oxidatively to inhibit AChE by the chemical treatment as well as the micromosal NADPH system.