Biochemical properties of plasma cholinesterase of significance to the anaesthetist are reviewed. The role of the genetic variants of the enzyme in suxamethonium sensitivity and hyperthermia are discussed with emphasis on the pregnant patient. Altered gene frequencies of the enzyme variants in some mental disorders is commented upon.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2044.1980.tb03800.x

Plasma cholinesterase variants and the anaesthetist.

https://deepblue.lib.umich.edu/bitstream/handle/2027.42/28774/0000606.pdf?sequence=1

Genetic variants of human serum cholinesterase influence metabolism of the muscle relaxant succinylcholine.

SUMMARY

1. Data from electrophoretic surveys of enzymes in European populations are reviewed.



2. Out of the seventy-one structural gene loci determining enzyme structure which have been scrutinized electrophoretically, 20 (28 %) were found to show genetic polymorphism. The average heterozygosity per locus for alleles determining electrophoretic variants is estimated at 0·067.



3. These results are compared with data from some other species.



4. For several different reasons, most of which relate to the techniques used and the enzymes and tissues surveyed, it seems likely that the present data considerably underestimate the true incidence of polymorphism and average heterozygosity per locus.

Average heterozygosity per locus in man: an estimate based on the incidence of enzyme polymorphisms

Es wird uber ein einfaches, schnell durchzufuhrendes Verfahren zur Bestimmung der Aktivitat der Pseudocholinesterase im Serum berichtet. Das Verfahren kann als Makro- oder Mikromethode angewandt werden und ist gut reproduzierbar. Es verwendet als Substrat Butyrylthiocholinjodid, das von PsChE umgesetzt wird. Das freigesetzte Thicholin reduziert 5,5-Dithiobis-2-nitrobenzoat zu gelb gefarbtem 5-Mercapto-2-nitrobenzoat; die Geschwindigkeit der Farbbildung (als kinetisches Verfahren angewandt) ermoglicht die Ermittlung der PsChE-Aktivitat. Die Bestimmung wird durch die Acetylcholinesterase der Erythrocyten bei Hamolyse nicht gestort.

[A kinetic method for determination of the activity of pseudocholinesterase (acylcholine acyl-hydrolase 3.1.1.8.)].

Publisher Summary This chapter presents a discussion of plasma cholinesterases. The whole field of cholinesterase polymorphism, and much of pharmacogenetics, is opened up by the clinical observation that in certain patients receiving succinylcholine, prolonged apnea developed. The best known clinical application of cholinesterase assay concerns the abnormally prolonged effect of the muscle relaxant succinylcholine that is found in a small proportion of patients. The cholinesterases are accepted as being synthesized in the liver and the assay of cholinesterase first became of interest to the clinician and to the clinical chemist as a test of liver function. Low serum cholinesterase activities are found in acute hepatitis, acute cirrhosis, and in liver metastases in those conditions where the hepatic synthesis of the protein is impaired. The synthesis of several other proteins is also reduced in such conditions, so that cholinesterase assay has been largely superseded as a test of liver function by measurements related to proteins such as albumin and prothrombin. Recommended procedures for collecting and storing plasma and serum specimens and laboratory procedures used for distinguishing the more common serum cholinesterase variants are also discussed in the chapter.

The plasma cholinesteerases: a new perspective.

The results of a comparison of the actions of individual human sera support evidence previously obtained for the existence of two different types of pseudocholinesterase in man. Maximum rates of hydrolysis of choline esters by human sera containing the normal type of cholinesterase were two to four times greater than the maximum rates obtained with sera containing atypical esterase. Human sera with the normal type of cholinesterase hydrolyzed butyrylcholine at a considerably faster rate than pentanoylcholine; atypical esterase hydrolyzed pentanoylcholine at approximately the same rate as butyrylcholine. All Michaelis constants for the normal enzyme were lower than those for the atypical enzyme by a factor which varied from 1.4 to 6.4. The data were compatible with the assumption of a linear relationship between the log of the Michaelis constants and the number of acyl carbons in the choline esters, but the slopes differed significantly for the two enzymes. For a homologous series of choline esters, there ...

R. O. Davies

Papers

The action of normal and atypical cholinesterase of human serum upon a series of esters of choline