Pralidoxime hydrolysis of thiocholine esters

Pralidoxime (2-PAM) hydrolyzes both acetylthiocholine and butytylthiocholine in an apparent first-order manner, with higher rates observed at pH 8.0 compared to those at pH 7.4. When the reaction is followed by the decrease in pH due to hydrolysis, pralidoxime hydrolyzes acetylthiocholine but not acetylcholine or succinylcholine. This implies that, while pralidoxime acts to reverse intoxication by organophosphate compounds due to the otherwise irreversible inhibition of acetylcholinesterase, it does not also supplement this detoxification by hydrolysis of the enzyme's substrate, acetylcholine.