Acetylcholinesterase

Acetylcholinesterase is an enzyme that rapidly hydrolyzes acetylcholine into choline and acetate, ending signaling at cholinergic synapses and neuromuscular junctions.

Acetylcholine: Acetylcholine is a neurotransmitter and signaling molecule used by neurons, muscles, and other cells. It is the substrate whose breakdown terminates cholinergic signaling.
Acetylcholinesterase inhibitor: An acetylcholinesterase inhibitor is a substance that reduces or blocks the enzyme's activity. Inhibition slows acetylcholine breakdown and increases cholinergic signaling.
Enzyme: An enzyme is a biological catalyst that accelerates chemical reactions without being consumed. Acetylcholinesterase is a specialized enzyme with exceptionally rapid catalytic turnover.
Cholinesterase: Cholinesterases are enzymes that hydrolyze choline esters, including acetylcholine. Acetylcholinesterase is the specialized cholinesterase most associated with synaptic transmission.
Cholinergic synapse: A cholinergic synapse is a junction where a neuron communicates using acetylcholine. Acetylcholinesterase clears acetylcholine from these signaling junctions.
Donepezil: Donepezil is a reversible acetylcholinesterase inhibitor used to treat symptoms of Alzheimer's disease. It is a clinically used example of targeting the enzyme in the brain.
Active site: An active site is the region of an enzyme where substrates bind and chemical reactions occur. Acetylcholinesterase's deep active-site gorge guides acetylcholine to catalytic residues.
Cholinergic signaling: Cholinergic signaling is communication mediated by the neurotransmitter acetylcholine. The enzyme evolved as a fast termination mechanism for this signaling.
Catalytic triad: A catalytic triad is a three-residue arrangement that enables chemical reactions in many enzymes. Its serine, histidine, and glutamate residues drive acetylcholine hydrolysis.
Neostigmine: Neostigmine is a reversible acetylcholinesterase inhibitor used in conditions including myasthenia gravis. Its inhibition increases acetylcholine at neuromuscular junctions.

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