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Pseudocholinesterase () (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.
The 3D structure of acetylcholinesterase was first determined in 1991 by Joel Sussman et al. using protein from the Pacific electric ray.
Clinically-useful quantities of butyrylcholinesterase were synthesized in 2007 by PharmAthene, through the use of genetically-modified goats.
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.
Outside of biochemical warfare, anticholinesterases are also used for reversing medication induced paralysis during anesthesia; as well as in the treatment of myasthenia gravis, glaucoma, and Alzheimer's disease. Such compounds are used for killing insects in a range of products including sheep dip, organophosphate pesticides, and carbamate pesticides. In addition to acute poisoning as described above, a semi-acute poisoning characterized by strong mental disturbances can occur. Also, prolonged exposure can cause birth defects.
Category:Acetylcholine Category:Peripheral membrane proteins Category:EC 3.1.1
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