Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.11.1.7 (peroxidase)
 65,474 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

We describe an enzymic method for determining lecithin in amniotic fluid. Phospholipase D from savoy cabbage is used to liberate choline from lecithin, and the liberated choline is oxidized to betaine and hydrogen peroxide by choline oxidase from Arthrobacter globiformis. The hydrogen peroxide forms a colored complex with phenol and 4-aminoantipyrene in the presence of horseradish peroxidase, and this color is measured spectrophotometrically. The method is relatively easy, precise, and accurate, requires less time and sample than other methods, and offers a reliable alternative to the lecithin/sphingomyelin ratio techniques for assessing fetal lung maturity.
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PMID:Enzymic assay for lecithin in amniotic fluid. 76 44

A new enzymatic method is presented for the determination of serum choline-containing phospholipids with a combined enzymatic method using phospholipase D (from Streptomyces species), choline oxidase (from Arthrobacter species) and peroxidase. The method is reproducible, and the results correlate well with those obtained by the conventional digestion method (Hoeflmayr, J. and Fried, R. (1966) Med. Ernaehr. 7, 9-10). The method affords better specificity, requires a smaller quantity of the sample and shorter time than those previously reported, and has excellent precision.
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PMID:A new enzymatic method for determination of serum choline-containing phospholipids. 89 Sep 67

A sensitive flow injection analysis using luminol/peroxidase chemiluminescence was developed for the determination of choline-containing phospholipids in serum. Flow injection manifold was composed of two channel system with an enzyme column, in which phospholipase D was immobilized together with choline oxidase. The serum sample (5 microliters) was pretreated by Extrelut column (diatomite column) extraction with chloroform-methanol (95:5). The extract (20 microliters) was injected into a sample carrier at 38 degrees C and passed through the enzyme column, which converted phospholipid to choline and subsequently to hydrogen peroxide. Produced hydrogen peroxide was monitored by measuring the chemiluminescence intensity of luminol/peroxidase system at 5 degrees C. The response was linear against the amount of phospholipids ranging from 2 to 2000 pmol/test, and the relative standard deviation was less than 2%. In the determination of phospholipids in the serum, a correlation coefficient (r) between 4-aminoantipyrine/phenol and the proposed methods was found to be 0.983 (Y = 1.035X-6.2). The throughput rate was 15 samples/h.
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PMID:[Flow injection analysis for determination of choline-containing phospholipids by luminol chemiluminescence]. 157 43

A method is described for reversed-phase HPLC separation of acetylcholine and choline and of their homologues in tissue extracts or perfusion fluids, combined with postcolumn enzymatic derivatization and fluorometric quantification. The separation occurs on a polymeric resin derivatized with hydrophobic moiety and the mobile phase consists of Na2HPO4, 3-(p-hydroxyphenyl)propionic acid and sodium dodecylsulphate; postcolumn enzyme reactor contains immobilized acetylcholinesterase, choline oxidase, and peroxidase. The limits of detection are 1 pmol choline and 3 pmol acetylcholine per sample. The method is free of interferences encountered with electrochemical detection and well suited for non-attended automatic operation.
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PMID:Sensitive method for HPLC determination of acetylcholine, choline and their analogues using fluorometric detection. 157 98

A continuous spectrophotometric method for monitoring phospholipase D-catalyzed hydrolysis of long acyl chain phosphatidylcholines has been formulated at pH 8.0 in a mixed detergent system using the coupling enzymes choline oxidase and peroxidase. Standard curves for phosphatidylcholine determination in both end-point and rate modes are presented and applied to the estimation of that phospholipid in a solubilized human erythrocyte membrane sample. In rate mode the method is suitable for kinetic study of phospholipase D with physiological substrates in micellar form.
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PMID:A continuous spectrophotometric method for monitoring phospholipase D-catalyzed reactions of physiological substrates. 177 93

A fluorometric assay using 3-(p-hydroxyphenyl) propionic acid (HPPA) was conducted to determine the activity of pseudocholinesterase (ChE) [Enzyme Commission (EC) No. 3.1.1.8] in postmortem blood samples so as to test for organophosphate poisoning. By the enzymatic reaction of ChE, its substrate, benzoylcholine, produces choline, which is oxidized by choline oxidase to generate hydrogen peroxide. HPPA is oxidized by hydrogen peroxide and peroxidase to become the fluorogenic dimer whose concentration is measured fluorometrically at an excitation emission wavelength of 320 nm and an elimination emission wavelength of 404 nm. The selectivity and sensitivity of the present method were found to be superior to those of conventional pH and spectrophotometric methods.
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PMID:Fluorometric determination of pseudocholinesterase activity in postmortem blood samples. 226 69

Laboratory and clinical evidence of the inhibition of plasma cholinesterase by metoclopramide was demonstrated. When succinylcholine is used as the substrate and the product choline assayed by choline oxidase-peroxidase-quinone dye colorimetry, the rate of the choline production as optical density change was reduced to 50% by 19.5 X 10(-6) M metoclopramide at 20 degrees C. Prolongation of neuromuscular blockade produced by concurrent administration of succinylcholine and metoclopramide was studied in 22 patients aged between 18 and 40 years undergoing elective gynecological surgery. EMG activity in the adductor pollicis muscle was recorded in response to a train-of-four (TOF) stimulus delivered every 10 s. Patients were randomly divided into two groups: A and B. In both groups, anesthesia was induced with thiopental and maintained with sufentanil and nitrous oxide. Tracheal intubation followed intravenous succinylcholine. Intraoperatively, after returning of neuromuscular function, patients in both groups received 20 mg succinylcholine for the determination of duration of neuromuscular blockade. Time from 95% suppression of baseline twitch following a 20 mg increment of succinylcholine until recovery to 25% of control activity was determined. Thereafter, in group A, patients receive metoclopramide (10 mg iv) followed by succinylcholine 20 mg iv, and patients in group B received succinylcholine 20 mg iv alone. Recovery times were again measured and found to be prolonged in patients receiving metoclopramide compared with those not receiving metoclopramide (P less than 0.05). Metoclopramide has no intrinsic neuromuscular blocking activity, but its ability to inhibit plasma cholinesterase probably is the mechanism by which it prolongs succinylcholine block. Reducing the dose of succinylcholine may be appropriate when metoclopramide is given concurrently.
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PMID:Prolongation of succinylcholine block by metoclopramide. 265 89

A method for determination of picomolar quantities of acetylcholine and choline in solutions and tissue extracts is described. The analytes are injected into a continuous stream of a simple medium flowing through a sequence of enzyme reactors containing acetylcholinesterase, choline oxidase, and peroxidase. Additional reactors with choline oxidase and catalase are used to remove endogenous choline from the tissue extracts in which the content of acetylcholine is to be measured. Reaction products are detected fluorometrically or luminometrically. The limits of sensitivity are about 10 pmol/sample with luminometric and 0.2 pmol/sample with fluorometric detection.
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PMID:Determination of acetylcholine and choline by flow-injection with immobilized enzymes and fluorometric or luminometric detection. 274 18

A sensitive fluorogenic assay for acetylcholine is described. The assay is based upon the reactions: (1) hydrolysis of acetylcholine to choline and acetate, catalyzed by acetylcholinesterase. (2) Oxidation of choline to betaine and hydrogen peroxide by choline oxidase. (3) Oxidation of p-hydroxyphenylacetic acid by hydrogen peroxide to a fluorescent product, catalyzed by peroxidase. With a sensitivity comparable to chemiluminescence procedures, the assay should find application to those situations requiring the persistence of a fluorescence signal or the necessity of assaying small volumes.
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PMID:A fluorometric assay for acetylcholine with picomole sensitivity. 276 Dec 99


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