Fredriksson_1960_Biochem.Pharmacol_3_184

The spontaneous reversal of cholinesterase activity has been studied following inhibition with methylfluorophosphorylcholine, methylfluorophosphorylcarbocholine (3 : 3-dimethylbutoxyphosphoryl fluoride) and isopropoxymethylphosphoryl fluoride (Sarin). Aceto- and butyrocholinesterase have been used as enzyme sources, and the reversal of enzyme activity has been studied at 4degr, 25degr and 35degr. Inhibition produced by the two phosphorylcholines is readily reversible in contrast to that produced by Sarin. This is explained in terms of formation of an enzyme-inhibitor complex of another type than the one produced by Sarin. The results also supports the theory that butyrocholinesterase lacks an anionic site, and they confirm the previous observation that in intact animals methylfluorophosphorylcholines produce symptoms of shorter duration than ordinary organophosphorus cholinesterase inhibitors.