QM/MM study on the spontaneous reactivation mechanism of (±)methamidophos-inhibited-acetylcholinesterase

► The key intermediates exhibit the trigonal bipyramidal character. ► The rate-determining step of the three studied paths were provided. ► A dominate reactivation pathway of (+)-MeP-inhibited human AChE was found. ► (−)-MeP-inhibited AChE is less feasible to be spontaneously reactivated.