Selective Inhibition of Pseudo‐cholinesterase by Diisopropyl Fluorophosphonate

The inhibition of cholinesterase by fluorophosphonates was discovered in 1941 by In 1941 McCombie and Saunders prepared diisopropyl fluorophosphonate and At that time it was not known that there were two enzymes, true cholinesterase and pseudo-cholinesterase (Mendel and Rudney, 1943a), which are not necessarily affected similarly by inhibitors In the experiments to be reported in this paper it will be shown that diisopropyl fluorophosphonate, unlike eserine or prostigmine (Hawkins and Mendel, 1946, and unpublished experiments), exhibits a much stronger inhibitory action on pseudo-cholinesterase than on true cholinesterase. With low concentrations of diisopropyl fluorophosphonate it is therefore possible to inhibit pseudo-cholinesterase selectively without affecting true cholinesterase.