The Pseudocholinesterase Variants. Esterase Levels and Dibucaine Numbers in Families Selected Through Suxamethonium Sensitive Individuals

Complete Pseudocholinesterase Deficiency: Genetic and Immunologic Characterization*

“…Individuals sensitive to suxamethonium are either homozygous or mixed heterozygous for the mutant genes E1R and Elf or the "silent" gene. All presently available pedigree data and considerations based on population genetics suggest that the "silent" gene is an allele of the normal esterase gene and its two allelic mutants (8,9,11,23). The kindred presented here provides further evidence against the alternative hypothesis (8) (25,26).…”

“…Family data fit the hypothesis that both variants are determined by mutant genes (Ela and El') allelic to the gene determining the normal enzyme (Elu) (4,6,23,24). Table I presents all of the known phenotypes and genotypes of the pseudocholinesterase system along with their associated laboratory findings and population frequencies.…”

Assay of Cholinesterase in Clinical Chemistry

“…The use of 37°C would permit a better separation of the phenotypes. This reasoning received support from the work of Lehmann and his associates (Lehmann et al, 1958;Harris et al, 1960) (see sections 7.3 and 7.3.1), who conducted their estimations at 37"C and found a better correlation between cholinesterase activity and suxamethonium activity than others who used a lower reaction temperature (Bush, 1961).…”

“…The heterozygotes, presumably possessing a mixture of both enzymes, were usually found to have intermediate levels of activity. However, in certain families, it was observed that one of the parents or children of an 'atypical' individual appeared to have only the 'usual' type enzyme (Kalow and Staron, 1957;Harris et al, 1960;Liddell et al, 1962b). A possible explanation for these findings was offered by Kalow and Staron (1957).…”

Assessment of Enzyme Inhibition: A Review with Examples from the Development of Monoamine Oxidase and Cholinesterase Inhibitory Drugs<strong> </strong>

“…Tetraisopropyl pyrophosphoramide (iso-OMPA) and ethopropazine (profenaminerofenamine) have been used for this purpose [81]. Its activity towards succinylcholine (suxamethonium), which has been used as a muscle relaxant during surgery, resulted in the identification of individuals with an unusual variant of BChE that had reduced activity and does not metabolize succinylcholine efficiently [83], leading to a prolonged and potentially fatal muscle-paralyzing action of this drug. The fact that such individuals appeared to exhibit no other deleterious effects, strengthened the view that the main role of role of BChE was that of a scavenger in peripheral tissues.…”