Action of Organophosphorus Compounds Upon Esterases of Human Liver

Human serum and liver esterases separated electrophoretically in starch gel were exposed to two series of organophosphorus insecticides. One series consisted of compounds active per se, the other of analogues requiring metabolic or chemical conversion to produce potent anticholinesterases. The results indicated that only one fraction of the liver, designated as zone L-2, is inhibited by low concentrations of all insecticides. This fraction shows a similar pattern of susceptibility to different inhibitors as does human serum cholinesterase. Of the other two zones of activity in liver, zone L-1 was found to be more susceptible to activated thionate, dithioate, and thioether derivatives than was zone L-3, while the latter zone was more susceptible to phosphates active per se.