An allosteric site is a site other than the active site of an enzyme where a regulator can attach to either activate or inhibit the enzyme. After it has attached to the allosteric site, the inhibitor alters the shape of the active site and hence the enzyme can no longer bind with its substrate.
Acetylcholinesterase (AChE) has one known peripheral allosteric subsite that is responsible for the amyloidosis in Alzheimer's disease through interaction with amyloid B-peptide (Roca, et al, 2018). However, in their research, the group also discovered two more allosteric sites on the AChE molecule through computational tools. The two sites allowed them to identify allosteric inhibitors by virtual screening.
Other researchers had predicted earlier the possibility of having more than one allosteric site on AChE. For instance, Changeux et al (1966) had shown that Acetylcholine and Atropine arid 1-hyoscyamine binds to non-catalytic sites as well as to the active centre of the enzyme.
Kato, G., Tan, E., & Yung, J. (1972). Allosteric properties of acetylcholinesterase. Nature New Biology, 236(67), 185-185.
Roca, C., Requena, C., Sebastián-Pérez, V., Malhotra, S., Radoux, C., Pérez, C., ... & Campillo, N. E. (2018). Identification of new allosteric sites and modulators of AChE through computational and experimental tools. Journal of enzyme inhibition and medicinal chemistry, 33(1), 1034-1047.