LP14299-9

Cholinesterase

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Descriptions

In biochemistry, cholinesterase is a family of enzymes that catalyze the hydrolysis of the neurotransmitter acetylcholine into choline and acetic acid, a reaction necessary to allow a cholinergic neuron to return to its resting state after activation.

There are two types:
1. Acetylcholinesterase (EC 3.1.1.7) (AChE), also known as RBC cholinesterase, erythrocyte cholinesterase, or (most formally) acetylcholine acetylhydrolase, found primarily in the blood and neural synapses. Acetylcholinesterase exists in multiple molecular forms. In the mammalian brain the majority of AChE occurs as a tetrameric, G4 form (10) with much smaller amounts of a monomeric G1 (4S) form.
2. Pseudocholinesterase (EC 3.1.1.8) (BChE or BuChE), also known as plasma cholinesterase, butyrylcholinesterase, or (most formally) acylcholine acylhydrolase, found primarily in the liver.

The difference between the two types of cholinesterase has to do with their respective preferences for substrates: the former hydrolyses acetylcholine more quickly; the latter hydrolyses butyrylcholine more quickly.

The half-life of pseudocholinesterase is approximately 8-16 hours. Pseudocholinesterase levels may be reduced in patients with advanced liver disease. The decrease must be greater than 75% before significant prolongation of neuromuscular blockade occurs with succinylcholine.

An absence or mutation of the pseudocholinesterase enzyme leads to a medical condition known as pseudocholinesterase deficiency. This is a silent condition that manifests itself only when people that have the deficiency receive the muscle relaxants succinylcholine or mivacurium during a surgery.
Pseudocholinesterase deficiency may also affect local anaesthetic selection in dental procedures. The enzyme plays an important role in the metabolism of ester-based local anaesthetics, a deficiency lowers the margin of safety and increases the risk of systemic effects with this type of anaesthetic. The selection of an amide-based solution is recommended in such patients.
Elevation of plasma pseudocholinesterase was observed in 90.5% cases of acute myocardial infarction.
The presence of acetylcholinesterase in the amniotic fluid may be tested in early pregnancy. A sample of amniotic fluid is removed by amniocentesis, and presence of AChE can confirm several common types of birth defect, including abdominal wall defects and neural tube defects.
Butyrylcholinesterase can be used as a prophylactic agent against nerve gas and other organophosphate poisoning Copyright Text is available under the Creative Commons Attribution/Share-Alike License. See http://creativecommons.org/licenses/by-sa/3.0/ for details. Source: Wikipedia, Cholinesterase (Wikipedia)

Cholinesterase is measured to diagnose organophosphate and carbamate toxicity or identify atypical enzyme forms. RBC levels measured to detect chronic exposure to systemic insecticides. Insecticides inhibit both RBC and plasma cholinesterase levels, but serum levels return to normal before RBC levels normalize. Cholinesterase is irreversibly inhibited by organophosphate insecticides and reversibly inhibited by carbamate insecticides. Information from LOINC partner 1 2006 10 24.

Pseudocholinesterase is also known as plasma cholinesterase, butyrylcholinesterase, or (most formally) acyl choline acylhydrolase, found primarily in the liver. An absence or mutation of the pseudocholinesterase enzyme leads to a medical condition known as pseudocholinesterase deficiency, which is a silent condition which only manifests itself when people who have the deficiency receive the muscle relaxants succinylcholine or mivacurium during surgery. Information from en.Wikipedia.org. Source: Regenstrief Institute

Basic Part Properties

Part Display Name

Cholinesterase

Part Type

Component (Describes the core component or analyte measured)

Created On

2000-05-04

Construct for LOINC Short Name

Cholinesterase

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