Title : Structure-activity relationship of reversible cholinesterase inhibitors including paraquat - Seto_1988_Arch.Toxicol_62_37
Author(s) : Seto Y , Shinohara T
Ref : Archives of Toxicology , 62 :37 , 1988
Abstract :

The inhibitory effect of paraquat on cholinesterase activity was investigated in comparison with four paraquat derivatives, six monoquaternary ammoniums and six anticholinergic drugs. Inhibitor concentrations to cause 50% inhibition (I50) and Hill coefficients for three enzymes, human erythrocyte acetylcholinesterase (AChE), Electrophorus electricus AChE and human plasma butyrylcholinesterase (BCHE) were measured. The results obtained were as follows. The I50 for erythrocyte AChE was similar to the I50 for eel AChE. Secondary to edrophonium, diethylparaquat, paraquat, morfamquat and monoquat showed lower I50 for AChE, and possessed higher inhibition selectivity (IS), expressed as the ratio of I50 for BCHE to I50 for erythrocyte AChE. However, diquat showed higher I50 for AChE and lower IS, similar to the other monoquaternary ammoniums. A negative correlation was observed between log [I50 for erythrocyte AChE] and log [IS], among paraquat and its derivatives, monoquaternary ammoniums and anticholinergic drugs, respectively. With respect to Hill coefficients, these inhibitors could be classified into four groups, [1] competitive inhibitors: diquat, edrophonium, choline, tetramethylammonium and trimethylphenylammonium, [2] inhibitors showing negative cooperativity: paraquat, diethylparaquat, morfamquat, d-tubocurarine, atropine, gallamine and nicotine, [3] moderate type inhibitors: monoquat, hexamethonium and decamethonium. [4] the other type inhibitors showing positive cooperativity for erythrocyte AChE: tetraethylammonium and ethyltrimethylammonium.

PubMedSearch : Seto_1988_Arch.Toxicol_62_37
PubMedID: 3190453

Related information

Inhibitor Atropine    D-tubocurarine    Decamethonium    Diethylparaquat    Edrophonium    Gallamine~Flaxedil    Hexamethonium    Monoquat    Morfamquat    Nicotine    Paraquat    Tetramethylammonium
Substrate Atropine    D-tubocurarine    Decamethonium    Diethylparaquat    Edrophonium    Gallamine~Flaxedil    Hexamethonium    Monoquat    Morfamquat    Nicotine    Paraquat    Tetramethylammonium    Atropine

Citations formats

Seto Y, Shinohara T (1988)
Structure-activity relationship of reversible cholinesterase inhibitors including paraquat
Archives of Toxicology 62 :37

Seto Y, Shinohara T (1988)
Archives of Toxicology 62 :37