The crystallographic structure of AChE reveals that it has a narrow 20 A gorge,containing two binging sites : the catalytic active site (CAS) at the bottom and the peripheral anionic site (PAS) near the entrance of the gorge.
hence,inhibitors that bind to either one or two sites could inhibit the AChE.
However, current studies indicated that AChE could promote amyloid fibril formation by interaction through the PAS of AChE,giving stable AChE-ab complex, which are more toxic than single AB peptides alone.