Hydrolysis and enzymatic degradation of Novichok nerve agents

Several parameters of the Novichok nerve agents A230, A232 and A234 were determined. Hydrolysis rates were approximately one to three orders of magnitude slower than G-type nerve agents and approximately zero to two orders of magnitude slower than V-type nerve agents. A230 was the most labile Novichok compound followed by A232 then A234. Activation energies (E_a) and frequency factors (A) were determined for all three compounds. The organophosphorus acid anhydrolase (OPAA) enzyme had catalytic efficiencies on the Novichok compounds ranging between 10⁴ and 10⁵ M^-1 min^-1 with the highest k _cat/K_m value for A230, then A232 and lastly, A234.