Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.11.1.7 (peroxidase)
 65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Methods for the determination of serum urate which employ the uricase-peroxidase reaction may suffer interference from concentrations of bilirubin which can be found in relatively mild jaundice. Such concentrations of bilirubin are also frequently present in sera distributed as part of an external quality assessment scheme and, for this reason, laboratories should be particularly careful not to recalibrate their urate assays to attempt to achieve results closer to the consensus mean.
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PMID:Effect of bilirubin on uricase-peroxidase coupled reactions. Implications for urate measurement in clinical samples and external quality assessment schemes. 202 44

The methods described in this paper are based on the uricase catalyzed oxidation of uric acid to allantoine and hydrogen peroxide. By making use of the catalytic activity of peroxidase the generated H2O2 is measured either spectrophotometrically with 3-methyl-benzothiazoline-2-one hydrazone (MBTH) and 3-dimethylaminobenzoic acid (DMAB) (M1) or fluorimetrically with tyramine (M2) or L-tyrosine (M3). The methods are simple, sensitive and selective. The procedures developed can be rapidly and readily performed on patient serum samples without deproteinization using 100 microliters and 5 microliters for colorimetric and fluorimetric assay, respectively.
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PMID:An enzymatic assay for the colorimetric and fluorimetric determination of uric acid in sera. 236 Aug 68

Uricase is a peroxisomal liver enzyme that catalyzes the oxidation of uric acid to allantoin during purine catabolism. It is present in vertebrates in most species of fish, amphibians, and mammals but its enzymatic activity is absent in hominoids. We have used Western blot analysis in a comparative study to establish a homology among uricases from different species of vertebrates. Using antibodies against denatured rat liver uricase, we have been able to detect for the first time cross-reactivity with the uricase of species ranging in the evolutionary scale from fish to primates (macaque). Our results suggest that these uricases have a common evolutionary origin. Our conclusion is also supported by the fact that uricase from different species exhibits identical tissue, subcellular localization, and similarity of molecular weights. This study was extended to include human liver samples. Using the same approach but with a more sensitive detection system (alkaline phosphatase instead of peroxidase), we did not detect polypeptide species related to rat uricase in human fetal or adult liver samples, which indicates that during hominoid evolution, the mutational event responsible for the loss of uricase activity in humans precluded formation of a translatable uricase mRNA.
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PMID:Uricase protein sequences: conserved during vertebrate evolution but absent in humans. 319 41

A simple spectrophotometric assay for serum guanase based on the oxidation of 2,2'-azino-di(3-ethylbenzthiazoline-6-sulphate) (ABTS) using xanthine oxidase, uricase and peroxidase is described and statistically examined through its application to normal and pathological sera. The method is very sensitive, precise (CV below 8.13%) and linear up to 152.5 U/l. Comparison with the methods of Hue & Free ((1965) Clin. Chem. 11, 708-715), and Giusti ((1974) In: Methods of Enzymatic Analysis, Bergmeyer, H. U., ed., p. 1086), and Ito et al. ((1981) Clin. Chim. Acta 115, 135-144) gave a good correlation (r greater than or equal to 0.969). The reference values for the ABTS-method are 2.93 to 23.92 U/l (mean = 13.57 U/l, CV = 22.43%). The mean values of guanase activities determined in sera of patients with different liver diseases (mean = 30.29 U/l), or chronic alcoholics (mean = 35.41 U/l) were significantly higher than normal. The patients with chronic diseases had significantly lower activity (mean = 7.22 U/l, t = 9.25, p less than 0.001).
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PMID:Evaluation of the spectrophotometric assay of guanase with 2,2'-azino-di(3-ethylbenzthiazoline-6-sulphonate) (ABTS) as chromogen. 374 3

A new method for the determination of xanthine oxidase activity, based on the oxidation of 2,2'-azino-di(3-ethylbenzthiazoline-6-sulphonate) (ABTS) by use of uricase and peroxidase, is described. The absorbance increase of the oxidized form of ABTS, measured after 10 min at 410 nm is proportional to xanthine oxidase activity. The method is sensitive, precise (CV below 8.3%), and linear up to 20 U/l. The analytical recovery of the ABTS-method was quantitative. Comparison with the UV and colorimetric NBT-method gave good correlation (r greater than or equal to 0.984). Reference values for serum xanthine oxidase activities determined with the new ABTS-method on 83 healthy persons are 0 to 1.20 U/l.
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PMID:Spectrophotometric assay of xanthine oxidase with 2,2'-azino-di(3-ethylbenzthiazoline-6-sulphonate) (ABTS) as chromogen. 380 44

1. Homogenates of guinea-pig polymorphonuclear leucocytes were separated by differential centrifugation into six particulate fractions and a soluble fraction. 2. The distributions in these fractions of protein, DNA, succinate dehydrogenase, beta-glucuronidase, peroxidase, alkaline phosphatase, acid phosphatase (against p-nitrophenyl phosphate and beta-glycerophosphate), cathepsin, and catalase were compared. 3. Almost all of the DNA sedimented in the first two pellets, indicating that the nuclei were relatively intact. 4. The four hydrolases and peroxidase showed different distribution patterns, although these activities were previously reported to be localized mainly in the single ;granule' fraction isolated from leucocytes. 5. The particles containing peroxidase, acid phosphatase and alkaline phosphatase all exhibited latency. Maximum activity for each enzyme was obtained at roughly similar concentrations of Triton X-100. 6. The acid phosphatase of these cells was distributed between two populations of particles that differed in both sedimentation characteristics and density. The acid phosphatase(s) of the two populations showed slightly different substrate specificities. This bimodal distribution was not an artifact of the procedure used to elicit the cells. 7. Catalase was recovered almost entirely in the soluble fraction and showed no latency in freshly prepared homogenates. No urate oxidase was detected. 8. We conclude that the ;granule' fraction of the polymorphonuclear leucocyte, as isolated by previous workers, contains at least three, probably more, populations of particles with different enzyme contents, and that these cells probably do not contain peroxisomes.
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PMID:The distributions of some granule-associated enzymes in guinea-pig polymorphonuclear leucocytes. 541 96

We describe evidence that serum samples from patients with chronic renal failure possess a constituent that interferes with the measurement of uric acid when using a method employing uricase with peroxidase-assisted detection of the hydrogen peroxide generated. The interference is also reflected in reduced recovery of both hydrogen and sarcosine when added to serum from patients with chronic renal failure. The interferent may be protein in nature or protein bound, as the poor recovery of hydrogen peroxide is seen in patients' serum before and after haemodialysis.
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PMID:Interference in colorimetric reactions for measuring hydrogen peroxide. 621 15

We describe the problems encountered with the adaptation of two enzymatic assays for uric acid to a centrifugal analyser. A method employing the uricase/catalase/aldehyde dehydrogenase enzyme system sometimes suffered from interference due to light-scattering species in samples and reagents. The second method employing the uricase/peroxidase system gave results that were lower than the comparison method.
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PMID:Problems associated with the measurement of uric acid using two enzyme-mediated reaction systems. 650 11

A spectrophotometric method for the determination of serum uric acid based on the oxidation of 2,2'-azino-di(3-ethylbenzthiazoline-6-sulphonate) by use of uricase and peroxidase has already been reported. The method is very precise (CV less than 4.7%). The standard curve is linear up to 4640 mumol/L. Comparison with other enzymatic methods gave good correlation. The method gave results 9% lower than the phosphotungstate method. The effects of bilirubin, haemoglobin, glucose, ascorbic acid, anticoagulants and purine compounds were studied. The reference values for this method are 140.8-407.8 mumol/L for female subjects and 145.6-514.7 mumol/L for male subjects.
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PMID:Evaluation of the enzymatic assay of serum uric acid with 2,2'-azino-di(3-ethylbenzthiazoline-6-sulphonate) (ABTS) as chromogen. 651 91

A method for the flow injection analysis of glucose and uric acid in serum using immobilized enzymes in column form and chemiluminescence detection is described. The method is based on the determination of chemiluminescence formed by the reaction of a luminol-ferricyanide mixture with hydrogen peroxide which is produced by the action of the respective oxidases on glucose and uric acid. Glucose or uric acid in serum were determined with 1 microliter of the sample at a speed of 120 samples/h without carryover and at an assay time of approximately 10 s. The immobilized glucose oxidase column measured only 1.0 X 5 mm, and the immobilized uricase column 1.0 X 20 mm. The present method gave perfect linearity of the data up to 4.0 g glucose per liter or 0.10 g uric acid per liter with satisfactory precision, reproducibility, and accurate reaction recoveries. Furthermore, the present method was hardly affected by ascorbic acid, while the peroxidase-linked colorimetric method is usually influenced significantly by ascorbic acid. Both column reactors showed good operational stability for a 2-month period, during which time they were repeatedly used for analyses over 2000 times. The results on glucose and uric acid correlated satisfactorily with those obtained by other well-established methods.
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PMID:Highly sensitive flow injection analysis of glucose and uric acid in serum using an immobilized enzyme column and chemiluminescence. 652 74


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