Cholinesterase (Acetylcholinesterase and Butyrylcholinesterase) (ChE)

Cholinesterases are a family of enzymes responsible for the rapid hydrolysis of the neurotransmitter acetylcholine into choline and acetic acid (StatPearls, 2023) [3]. This group primarily consists of two types: acetylcholinesterase (AChE), found in erythrocytes, nerve synapses, and neuromuscular junctions, and butyrylcholinesterase (BChE), found in the plasma and liver (UniProt P22303, P06276) [1, 2]. AChE is essential for terminating synaptic transmission to prevent continuous muscle activation or nerve firing, while BChE serves a broader role in metabolizing various esters and drugs (PubMed, 2021) [5]. In clinical practice, these enzymes are major therapeutic targets for treating neurodegenerative conditions like Alzheimer's disease and autoimmune disorders like myasthenia gravis (NIH, 2022) [6]. They are also critical markers for diagnosing exposure to organophosphate pesticides and nerve agents, which irreversibly inhibit their activity (CDC, 2023) [7]. Furthermore, genetic variations in plasma cholinesterase can lead to prolonged paralysis following the administration of neuromuscular blockers like succinylcholine (StatPearls, 2023) [8].

Other names

AcetylcholinesteraseButyrylcholinesteraseTrue cholinesterasePseudocholinesteraseSerum cholinesteraseErythrocyte cholinesterasePlasma cholinesteraseAcylcholine acylhydrolase

Cholinesterase inhibitors bind to the active site of the enzyme (either reversibly or irreversibly), preventing the hydrolysis of acetylcholine. This leads to an accumulation of acetylcholine in the synaptic cleft or neuromuscular junction, enhancing and prolonging cholinergic transmission at nicotinic and muscarinic receptors (StatPearls, 2023) [3]. Reactivators like pralidoxime work by removing the inhibitor from the enzyme's active site, restoring its function (StatPearls, 2023) [3].