Countermeasures Against Organophosphorus Nerve Agents – Reactivation of Acetylcholinesterase
Organophosphate nerve agents, such as sarin gas, bind irreversibly to the enzyme acetylcholinesterase. The phosphylated enzyme is completely nonfunctional which leads to a toxic accumulation of the neurotransmitter acetylcholine.

Current antidotes utilize nucleophilic oximes to reactivate acetylcholinesterase by competitively binding to the phosphorous.