The bisquaternary ligand are oriented along the narrow gorge of AChE leading to the active site\; one quaternary group is apposed to the indole of Trp-84 and the other to that of Trp-279, near the top of the gorge. Ligands of both the CAS (catalytic active site) and the PAS (peripheral active site). The PAS is supposed to be part of some of the non catalytic properties od ACHEs