ACHE and Alzheimer disease: Dual binding site AChE inhibitors (i.e., such inhibitors that bind simultaneously to PAS and CAS of AChE) are attractive dual action AD drug candidates because they: (1) increase the concentration of the neurotransmitter ACh and (2) inhibit the AChE promoted formation of amyloid fibrils (a component in senile plaques23) when the PAS interacts with Aβ-proteins.24