[Heightened anticholinesterase activity of chlorophos in its interaction with the TMB-4 reactivator in vitro].

Experiments in vitro demonstrated that a thermostatic treatment of an aqueous chlorophos solution at 38 degrees is attended by its increased cholinesterase activity. The speed of the process is much higher in an alkaline medium. A joint incubation of chlorophos with the TMB-4 reactivator of pH of 7.5 and 38 degrees not only fails to result in decomposition of the poison, but on the contrary, tends to speed up the progressive accretion of the inhibitory properties of this organophosphorus compound. The author considers the data obtained as one of the proofs pointing to the formation during direct interaction of TMB-4 with chlorophos or the product of its transformation of a stable complex appearing to be a powerful anticholinesterase agent.