Kinetic analysis of the “substrate protective effect” in cholinesterases of different origin

The authors’ own and literature data are summarized on interaction of 17 irreversible organophosphorus inhibitors with different types of cholinesterases (ChE): erythrocyte acetylcholinesterase (AChE), serum butyrylcholinesterase (BuChE), and cholinesterase of the Pacific squidTodarodes pacificus, in the presence of 9 substrates. The kinetic analysis of the “substrate protective effect” based on A.P. Brestkin’s equation is performed, and the current interpretation of individual components of this process is done. An essential effect of the inhibitor structure on individual phases of the reaction is revealed. Among choline substrates, only formylcholine did not show a protective effect. The inability of an uncationic substrate, phenylacetate, to regulate ChE reactivity is confirmed. Among the studied ChE, the highest substrate protective effect was revealed in the Pacific squid ChE.