The nerve agent tabun inhibits acetylcholinesterase (AChE; EC 184.108.40.206) by the formation of a covalent bond with
the enzyme. Afterwards, AChE is not able to fulfil its role in the organism and subsequently cholinergic crisis
occurs. AChE reactivators (pralidoxime, obidoxime and HI-6) as causal antidotes are used for the cleavage of
the bond between the enzyme and nerve agent. Unfortunately, their potency for reactivation of tabun-inhibited
AChE is poor. The aim of the study was to choose the most potent reactivator of tabun-inhibited AChE. We have
tested eight AChE reactivators – pralidoxime, obidoxime, trimedoxime, HI-6, methoxime, Hlö-7 and our newly
synthesized oximes K027 and K048. All reactivators were tested using our standard in vitro reactivation test (pH
8, 25°C, time of inhibition by the nerve agent 30 minutes, time of reactivation by AChE reactivator 10 minutes).
According to our results, only trimedoxime was able to achieve 50% reactivation potency. However, this relatively
high potency was achieved at high oxime concentration (10-2 M). At a lower concentration of 10-4 M (the
probably attainable concentration in vivo), four AChE reactivators (trimedoxime, obidoxime, K027, and K048)
were able to reactivate AChE inhibited by tabun reaching from 10 to 18 %.
acetylcholinesterase – reactivators – nerve agents – tabun – oximes