Acetylcholinesterase inhibition by substituted phenyl N-alkyl carbamates
Yu, C.C.; Kearns, C.W.; Metcalf, R.L., 1972: Acetylcholinesterase inhibition by substituted phenyl N-alkyl carbamates. Journal of Agricultural and Food Chemistry 20(3): 537-540
Acetylcholinesterase (AChE, EC 3.1.1.7) inhibition constants (binding, carbamylation, reactivation, and overall bimolecular rate constants) were studied for selected substituted phenyl N-alkylcarbamates. N-Methylcarbamates were better inhibitors than larger N-alkylcarbamates. AChE from different species of animals showed remarkable species specificity toward these inhibitors. N-Ethylcarbamates were the least potent inhibitors of bovine erythrocyte AChE, while N-n-butyl or N-n-hexylcarbamates were the least potent inhibitors of AChE from the house-fly (Musca domestica L.), honey bee and house cricket (Acheta domesticus (L.)). Thus, short-chain N-alkyl (N-methyl to N-n-propyl) carbamates favoured the inhibition of insect AChE, while longer N-alkyl (N-n-butyl and higher) carbamates favoured the inhibition of bovine erythrocyte AChE. AChE inbibited by short-chain N-alkylcarbamates recovered its activity faster than the long-chain N-alkylcarbamates. Bovine erythrocyte AChE inhibited by carbamates recovered its activity much faster than insect AChE, especially when the inhibition was made by long-chain N-alkylcarbamates. Insecticidal activity was decreased when N-alkyl chain-length was increased.