On Genetically Determined Human Serum Cholinesterases

Abstract

The existence of genetically determined human serum cholinesterase variants (acylcholine acyl-hydrolase; EC 3.1.1.8) has been recognized by the use of a short acting muscle relaxant, suxamethonium. This polymorphism is now explained by at least four alleles belonging to an autosomal locus Ch(1) or E(1) depending on the nomenclature. These are: the usual gene, the dibucaine-resistant gene, the fluoride-resistant gene and the silent gene. At present, the modes of transmission for the silent genes is confusing and lack proper understanding. Another variant, not an allele of the first group, is recognized by gel electrophoresis, belong to a second locus Ch(2) or E(2). Evidence has been presented that many more rare serum cholinesterase variants may exist. Besides these genetic variants, normal serum cholinesterase is known to exist in multiple molecular forms. The present article attempts to discuss the polymorphism of human cholinesterase in relation to their chemical and genetic characteristics and their possible function.

Measurement of Erythrocyte Acetylcholinesterase and Plasma Cholinesterase Activity by a Differential pH Technique

“…1, 23 At a final concentration of 4·4 umol/L, we found a 90% inhibition of plasma cholinesterase, without any significant inhibition on the erythrocytic fraction, in agreement with Lewis.P The interference of the residual plasma cholinesterase activity during the erythrocyte cholinesterase determination on whole blood is negligible, considering the small volume of plasma used and the enzyme concentration, much lower in plasma than in erythrocytes.…”

“…I. 23 The buffer is stable at 4°C for 2 weeks in a dark bottle. The same mixture with KCI 50 mmol/L, but without quinidine sulphate, has been used for the determination of plasma cholinesterase.…”

THE EFFECT IN VITRO OF VOLATILE ANESTHETICS ON THE ACTIVITY OF CHOLINESTERASES1

“…For example, with choline esters of aliphatic acids, AChE, but not ChE, shows substrate inhibition. Also, both enzymes are inhibited by 10 pM-physostigmine, whereas 20 PMquinidine sulfate inhibits only the ChE enzyme (DAs, 1976). Within the class of AChE enzymes, phenylmethanesulfonyl fluoride inhibits bovine erythrocyte AChE (TURINI et d., 1969), but not the AChE enzyme from eel (FAHRNEY & GOLD, 1963).…”