Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.1.8 (cholinesterase)
 12,691 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A new enzymatic method for the determination of serum pseudo-cholinesterase activity is described. Choline, which is liberated from benzoylcholine as substrate by cholinesterase, is oxidized by choline oxidase to betaine with the simultaneous production of hydrogen peroxide, which oxidatively couples with 4-aminoantipyrine and phenol in the presence of peroxidase to yield a chromogen with maximal absorbance at 500 nm. The calibration curve is linear up to 1500 units per liter of serum. The method is reproducible, and the results correlate well with those obtained by the method using butyrylthiocholine as substrate and 5,5'-dithiobis-(2-nitrobenzoic acid) as color reagent.
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PMID:New enzymatic assay of cholinesterase activity. 2 Feb 53

Hydrolysis of ethers of saturated and unsaturated alcohols and ethers, e.g. phenol and choline, under the action of horse blood serum cholinesterase, was studied. The reactivity towards enzymatic hydrolysis is decreased due to a greater length of the chain in the alcohol residue of the benzoic acid aminoethers; at nCH2 = 4 the compound is a poor substrate. An increase in nydrophobicity of the acyl residue of the ether molecule also leads to a decrease in the Vmax and Km values. In case of cholinesterase substrates, an increase in the molecule hydrophobicity results in an increase of its non-productive absorption on the active surface of the enzyme, which decreases its hydrolysis. Aminobutynol benzoates are hydrolyzed by cholinesterase more rapidly as compared to the ethers of corresponding aminobutanols and their homologs.
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PMID:[Study of hydrolysis of aminoalcohol ethers, phenol and choline under the action of horse blood serum cholinesterase]. 103 47

14C-carbofuran penetrated readily into seeds of Vicia faba and the rate of penetration was found to be dose dependent. The percentage of bound residues was generally low and did not exceed 3% of the applied dose. When the bound residues were fed to rats 46% of the radioactivity was eliminated via CO2 and urine, while tissues contained 25%. Carbofuran phenol and 3-hydroxy carbofuran represented the main metabolites in the urine. These data indicate that bean-bound carbofuran residues are highly bioavailable to rats. Feeding mice with bound carbofuran residues for 90 days led to inhibition of erythrocyte cholinesterase activity after 30 days (35-40%) while the plasma enzyme remained unaffected. Serum transaminases and blood urea nitrogen were significantly elevated, indicating injury to hepatic and renal structures. The results strongly suggest that the bound residues can induce adverse biological effects in mice.
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PMID:Bioavailability to rats and toxicity in mice of carbofuran residues bound to faba beans. 152 62

A two-step colorimetric method that overcomes the difficulties of the classic 240 nm benzoylcholine assay for plasma cholinesterase has been adapted to a Cobas-Fara centrifugal analyser, using choline oxidase coupled with peroxidase/phenol/aminoantipyrine for detection of the choline produced. Reaction conditions of the main reaction are identical to those of the classical benzoylcholine assay. The described method was applied to 105 selected serum samples, previously classified by the Danish Cholinesterase Research Unit as homo- or heterozygous for the usual (U), atypical (A), fluoride-resistant (F), or silent (S) allelic variants. The method showed a distinct separation of the various phenotypes, with catalytic activity concentrations, dibucaine numbers, and fluoride numbers directly comparable to established reference values of the manual 240 nm benzoylcholine method.
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PMID:Plasma cholinesterase genetic variants phenotyped using a Cobas-Fara centrifugal analyser. 323 60

We describe an automated kinetic method that uses a single aqueous reagent to measure the in vitro hydrolysis of the muscle relaxant succinylcholine. The substrate succinylcholine is hydrolyzed by plasma cholinesterase (EC 3.1.1.8), and the choline produced is oxidized by choline oxidase (EC 11.3.17) in the presence of peroxidase, 4-aminophenazone and phenol, to yield a chromagen with maximum absorbance at 500 nm. The method is reproducible (CV 1.3%), correlates well with a manual procedure using the same substrate (r = 0.994, y = 0.99x - 0.25), and is linear to 150 U/L. The method is well suited to pre-operative screening and detection of "at-risk" individuals, as illustrated by the family of one patient who had a prolonged succinylcholine apnea.
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PMID:Screening for plasma cholinesterase deficiency: an automated succinylcholine based assay. 339 Sep 4

Serum cholinesterase (E.C. 3.1.1.8) was assayed with succinylcholine as a substrate. The reaction was coupled with choline oxidase and peroxidase in the presence of 4-aminoantipyrine and phenol to produce a red quinone dye that was measured spectrophotometrically. The method requires 25 microliter of sample in a total volume of 1.0 ml. The mean activity for 35 adults of the usual genotype was 74.4 +/- 28 U/l (range 24-125 U/l). Succinylcholine-sensitive individuals had activities below 18 U/l. The same serum samples also were assayed with propionylthiocholine as a substrate. Activities with the two substrates showed a coefficient of correlation of 0.980 (n = 68). However, the method using propionylthiocholine showed more overlap between the activities of succinylcholine-sensitive and insensitive individuals. Assay with succinylcholine thus may offer a more effective method of screening for sensitive individuals, since some escape detection by conventional genotyping with dibucaine and fluoride.
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PMID:Assay of serum cholinesterase with succinylcholine and propionylthiocholine as substrates. 388 94

We describe a new method for measuring the in vitro rate of hydrolysis of the muscle relaxant succinylcholine. This substrate is hydrolyzed by plasma cholinesterase (EC 3.1.1.8). The resulting choline is determined by measuring the hydrogen peroxide formed on its oxidation by choline oxidase (EC 1.1.3.17). This is done by use of phenol and aminoantipyrine coupled to peroxidase, and yields an intense chromophore, Amax 500 nm. The assay requires 0.1 mL of plasma, and is precise and specific. The CV was 2.7% within run, 7.3% between run. For the usual (U variant) enzyme the Km is 53 mumol/L. Enzyme activity is removed by anticholinesterase antiserum, and is inhibited by dibucaine with a Ki of 2 mumol/L. Ten samples can be assayed in duplicate in an hour. This method is suited to routine use in any laboratory that has a simple spectrophotometer. The mean activity in 11 individuals with the cholinesterase phenotype UU was 105 U/L, for seven UA heterozygotes 61 U/L, and for three AA homozygotes 4 U/L. To the extent allowed by extrapolation from in vitro to in vivo results, this method should increase diagnostic accuracy and may directly predict duration of succinylcholine-induced apnea.
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PMID:A new succinylcholine-based assay of plasma cholinesterase. 636 11

We report the evaluation of a new commercially available assay system for the determination of serum pseudocholinesterase (EC 3.1.1.8) catalytic activity, and its application to a kinetic analyser. The assay is based on the colorimetric method of Okabe et al. (Clin. Chim. Acta 80, 87-94 (1977]: choline, liberated from benzoylcholine by pseudocholinesterase, is oxidized by choline-oxidase (EC 1.1.3.17) to betaine with the simultaneous production of hydrogen peroxide, which oxidatively couples with 4-aminoantipyrine and phenol in the presence of peroxidase to yield a coloured compound with maximal absorbance at 500 nm. The procedure not only has the advantage of being continuous, colorimetric and totally enzymatic but also appears to be precise (between-day analysis gives coefficient of variation between 3.5 and 5.6%) and accurate; the results obtained from normal and pathological sera show excellent correlation with those obtained by the alternative procedures employing propionylthiocholine, acetylthiocholine and butyrylthiocholine as substrates.
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PMID:Evaluation of a new continuous colorimetric method for determination of serum pseudocholinesterase catalytic activity and its application to a centrifugal fast analyser. 651 97

A new assay has been developed for detection of butyrylcholinesterase (EC 3.1.1.8) activity based upon the change in absorbance of phenol red, caused by the release of butyric acid from the substrate. Using commercially available enzyme prepared from horse serum, linear, dose-related decreases in absorbance were obtained, generally with correlation values of 0.965 or greater. The assay was modified and used to detect enzyme activity in the supernatants from primary cultures of mouse hepatocytes. The enzyme-mediated response was inhibited by NN'-diisopropylphosphorodiamidic anhydride, a specific inhibitor of butyrylcholinesterase.
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PMID:A micro-method for the detection of butyrylcholinesterase secreted by hepatocytes in vitro. 671 85

A choline oxidase-peroxidase coupled enzyme procedures is proposed for the determination of cholinesterase activity in human serum. This system is not only kinetic and colorimetric but is also relatively quick and simple to perform. The initial comparisons suggest that this method correlates well with a commonly used propionylthiocholine-dinitrobis-(nitro-benzoic acid) technique. Large amounts of bilirubin in the sample appear to have only minor deleterious effects on the assay. Since there are only two reagents that may be premixed, the procedure appears to be amenable to automation. The use of a mixture of sodium 2-hydroxy-3,5-dichlorobenzenesulfonate and 4-aminoantipyrene in the peroxidase catalyzed indicator reaction provides for a marked increase in sensitivity over previously reported 4-aminoantipyrene-phenol systems. This augmented sensitivity provides for a relatively large reagent to sample ratio. In addition, the reagents lend themselves toward lyophilization or "dry-fill".
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PMID:A procedure for the kinetic colorimetric determination of serum cholinesterase activity. 713 38


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