Cholinesterase refers to enzymes that hydrolyze choline esters, primarily including acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). AChE specifically breaks down acetylcholine, terminating nerve impulse transmission at neuromuscular junctions and in the central nervous system. BChE metabolizes diverse esters and may participate in detoxification. Both exhibit high catalytic activity but differ in substrate preference. Organophosphate pesticides irreversibly inhibit AChE, causing toxicity; antidotes like oximes (e.g., pralidoxime) and atropine are used clinically. Cholinesterase inhibitors (e.g., donepezil) enhance cholinergic signaling in Alzheimer’s disease.