Cholinesterase
| acetylcholinesterase (Yt blood group) | |||||||
|---|---|---|---|---|---|---|---|
Diagram of Pacific electric ray acetylcholinesterase. From PDB: 1EA5. | |||||||
| Identifiers | |||||||
| Symbol | ACHE | ||||||
| Alt. symbols | YT | ||||||
| NCBI gene | 43 | ||||||
| HGNC | 108 | ||||||
| OMIM | 100740 | ||||||
| RefSeq | NM_015831 | ||||||
| UniProt | P22303 | ||||||
| Other data | |||||||
| EC number | 3.1.1.7 | ||||||
| Locus | Chr. 7 q22 | ||||||
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| butyrylcholinesterase | |||||||
|---|---|---|---|---|---|---|---|
| Identifiers | |||||||
| Symbol | BCHE | ||||||
| Alt. symbols | CHE1, CHE2, E1 | ||||||
| NCBI gene | 590 | ||||||
| HGNC | 983 | ||||||
| OMIM | 177400 | ||||||
| RefSeq | NM_000055 | ||||||
| UniProt | P06276 | ||||||
| Other data | |||||||
| EC number | 3.1.1.8 | ||||||
| Locus | Chr. 3 q26.1-26.2 | ||||||
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The enzyme cholinesterase (EC 3.1.1.8, choline esterase; systematic name acylcholine acylhydrolase) catalyses the hydrolysis of choline-based esters, several of which serve as neurotransmitters.:
- an acylcholine + H2O = choline + a carboxylate
These reactions are necessary to allow a cholinergic neuron to return to its resting state after activation. For example, in muscle contraction, acetylcholine at a neuromuscular junction triggers a contraction; but for the muscle to relax afterward, rather than remaining locked in a tense state, the acetylcholine must be broken down by a choline esterase.
Two types of cholinesterase have been characterized: acetylcholinesterase (also called choline esterase I or erythrocyte cholinesterase), found mainly in chemical synapses and red blood cell membranes, and butyrylcholinesterase (also called choline esterase II or plasma cholinesterase), found mainly in the blood plasma.