Emil Halámek

Reactivation of Immobilized Acetylcholinesterase–Tabun Complex by Methoxime and Its Homologues

Using an immobilized acetylcholinesterase–tabun enzyme–inhibitor complex, the reactivation efficacy of a homologous series of bispyridinium reactivators with increasing length of the alkylene chain between the pyridinium rings has been studied. The number of the alkylene groups in the chain ranged from one to six. N,N′-Monomethylenebis(4-pyridiniumaldoxime) dibromide (MMB-4) and N,N′-trimethylenebis(4-pyridiniumaldoxime) dibromide (TMB-4) are the most efficient reactivators of the series.

Reactivation of immobilized acetylcholinesterase‑tabun complex by pralidoxime, its isomers, and homologs

Reactivation efficacy of three homologous and three isomeric series of pralidoxime-type reactivators with aldoxime group in position 2, 3 and 4 of the heterocycle was tested in reactivation of tabun-inhibited AChE. The experiments were performed with immobilized and stabilized porcine brain AChE. The enzyme acticity was measured by Ellman method. Reactivation efficacy was determined by measurement of indicator fabric coloration intensity as a measure of AChE activity. Of the studied group of nine reactivators, isomers with the functional group in position 2 were the most effective. The highest value (30 %) for reactivation of inhibited AChE was found for 2PAE after treatment for 15 min at concentration 0.5 mg/cm3. The efficacy of the isomers decreased in the order ortho > para > meta. No marked effect on the efficacy of the reactivators was observed on prolongation of the reactivation time. The reactivators efficacy decreased with decreasing concentration of their solutions.

Efficacy of 2-PAM, TMB-4, HI-6, and Toxogonin in Reactivation of Immobilized Acetylcholinesterase Inhibited by Compound R-33

ABSTRACT Efficacy of reactivators 2-PAM, TMB-4, HI-6, and toxogonin in reactivation of acetylcholinesterase inhibited by compound R-33 has been studied. The study was performed with acetylcholinesterase immobilized and stabilized on a cotton fabric and with an indicator paper with acetylthiocholine iodide and 5,5′-dithiobis(2-nitrobenzoic acid). The enzyme activity was determined by measurement of remission changes of the fabric surface, caused by reaction of the chromogenic reagent with products of enzymatic hydrolysis of the substrate. The most potent of the reactivators studied was 2-PAM at concentrations 0.5 mg.cm−3 and 0.1 mg.cm−3. Effectivity of this reactivator was over 20%. At these concentrations, reactivator HI-6 was less effective. Efficacy higher than that of 2-PAM was observed only after 20 min at concentrations 0.05 mg.cm−3 and 0.01 mg.cm−3. For TMB-4 and toxogonin the reactivation values were about 10% after 10 min, whereas after 15 or 20 min these reactivators were ineffective.