Background: Acetylcholinesterase is a serine hydrolase that terminates the action of the
neurotransmitter acetylcholine by hydrolyzing it into acetic acid and choline.
Objective: The enzyme, containing an ellipsoidal structure, possesses three binding sites such as active
site (with catalytic anionic and esteratic subsites), aromatic gorge and peripheral anionic site, where the
inhibiting compounds interact. The acetylcholinesterase inhibitors bind to the enzyme and interfere with
the breakdown of acetylcholine, leading to the deposition of acetylcholine in the nerve synapses and causing
disrupted neurotransmission. Based on this principle of action, many therapeutic drugs for the
treatment of different diseases, pesticides and chemical warfare agents have been synthesized targeting
Conclusion: The present review summarizes the current knowledge about acetylcholinesterase, its
structure, function and biosynthesis, its inhibitors, and mode of action of inhibitors on it. Besides, the
review also presents an overview about the resistance mechanism that the organisms develop due to the
over-application of acetylcholinesterase inhibitors.