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)

The localization of mutarotase in rat kidney was investigated by fluorescein-labelled and peroxidase-labelled antibody techniques, and by method of isolation of the nuclei and cytoplasm in non-aqueous solvents. In these immunohistochemical studies, mutarotase was almost exclusively recognized in the nuclei of epithelial cells of renal tubules and glomeruli in rat. The specific activity of mutarotase was found to be 1.5 times higher in the nuclei (122 units/g dry wt) than that in the cytoplasm (80 units/g dry wt) isolated with non-aqueous solvents. These results suggest that mutarotase may be involved in the metabolism of D-glucose in nuclei.
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PMID:The localization of mutarotase in rat kidney. 11 52

A modification, utilising mutarotase, of an enzymic, colorimetric system for determining D-glucose with D-glucose oxidase, peroxidase, and ABTS was satisfactory for the assay of the anomers of D-glucose in aqueous solution. The time required for a single assay is approximately 10 min, and the lower limit is 0.4 microgram of D-glucose. The method is applicable to the anomer analysis of D-glucose released by enzymic hydrolysis of D-glucosides.
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PMID:Rapid and sensitive, colorimetric determination of the anomers of D-glucose with D-glucose oxidase, peroxidase, and mutarotase. 91 91

Milk samples were analyzed for their lactose content using flow injection analysis and incorporating immobilized beta-galactosidase or beta-galactosidase/mutarotase and glucose oxidase/peroxidase bioreactors. These enzymes were immobilized, under mild conditions, on to a 2-fluoro-1-methylpyridinium salt-activated Fractogel support. The use of a phosphate buffer (0.15 M) was found to facilitate the rapid mutarotation of alpha-D-glucose and hence could obviate the need for the more expensive mutarotase. The chromogenic agents of choice for monitoring the reaction were 3-methyl-2-benzothiazolinone hydrazone and 3-dimethylaminobenzoic acid. Linearity was observed over the concentration range 16-160 micrograms/ml using lactose standards (r = 0.996). Between 30 and 40 milk samples/h can be analyzed. Comparisons are made with existing HPLC and alkaline methylamine methods for a range of milk matrices. The FIA method consistently gives the lowest standard deviations and coefficient of variation for the various milk matrices analyzed.
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PMID:Flow injection analysis of lactose using covalently immobilized beta-galactosidase, mutarotase, and glucose oxidase/peroxidase on a 2-fluoro-1-methylpyridinium salt-activated Fractogel support. 190 11

An automatic, luminometric assay of glucose in samples of the extracellular water space obtained by microdialysis is described. The assay involves oxidation by glucose oxidase (EC 1.1.3.4) and mutarotation of glucose by aldose mutarotase (EC 5.1.3.3.). The H2O2 formed is subsequently determined in a reaction catalyzed by horseradish peroxidase (EC 1.11.1.7) using luminol as electron donor. The assay is linear between 0.01 and 1 nmol in the cuvette. The detection limit, defined as 3 standard deviations of the reagent blank, was 0.008 mumol/liter in the cuvette. A complete oxidation of glucose is obtained within 4 min and 25 samples are automatically assayed within 75 min. Addition of microdialysate sample obtained from human adipose tissue in vivo did not interfere with the standard curves. Glucose added to microdialysate resulted in a complete recovery compared to a H2O2 standard. Analytical interference from different factors was investigated. No interference was observed up to the following concentrations: 5 mumol/liter epinephrine, 1 mumol/liter norepinephrine, 100 mumol/liter insulin, 500 mumol/liter pyruvate, 50 mmol/liter lactate, and 1 mumol/liter ascorbate. The glucose values with the present method correlated strongly (r = 0.984) with values obtained using a routine method involving glucose oxidase and peroxidase.
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PMID:Glucose determination in samples taken by microdialysis by peroxidase-catalyzed luminol chemiluminescence. 204 27

A study of the reverse reaction of rat brain hexokinase (ATP:D-hexose 6-phosphotransferase, EC 2.7.1.1) has been performed using a photometric method based on a mutarotase-glucose oxidase-peroxidase-chromogen system to trap and visualize glucose, plus a glycerol kinase-glycerol system to trap ATP. Glucose 6-phosphate or 2-deoxyglucose 6-phosphate were used as phosphoryl donors at different concentrations of ADP. Variation of glucose 6-phosphate concentrations resulted in a biphasic curve from which apparent Km and Ki values of ca. 0.2 mM were calculated. In contrast, variation of 2-deoxyglucose 6-phosphate concentrations resulted in Michaelian kinetics with an apparent Km of 2 mM. The Km value for MgADP was 16 mM irrespective of the nature and concentration of the hexose 6-phosphate substrate. These results are fully consistent with an allosteric site for glucose 6-phosphate as an explanation for the inhibition of animal hexokinases by glucose 6-P and further indicate that the maximal rate is the parameter affected. From these observations and previous knowledge, the possible occurrence in animal hexokinases of a regulatory site for ATP to account for the competition between glucose 6-phosphate and ATP in the forward reaction is postulated.
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PMID:Allosteric inhibition of brain hexokinase by glucose 6-phosphate in the reverse reaction. 400 67

An amperometric flow system combined with a glucose oxidase-mutarotase reactor was optimized and used to determine aromatic amines and phenols using peroxidase-modified graphite electrodes. An increase in currents upon injection of the analyzed substrate was shown to be approximated by a Michaelis-Menten type dependence. The detection limit was calculated as 3 times the noise, and the sensitivity was calculated as Imax/K(m)app. Commercially available horseradish peroxidase was compared with tobacco anionic and peanut cationic peroxidases for determination of aromatic amines and phenols. Detection limits of 10 nM for determination of o-aminophenol and o- and p-phenylenediamine achieved with a tobacco peroxidase-modified electrode give a promise for further improvements in sensitivities and detection limits of biosensors.
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PMID:Bioelectrochemical monitoring of phenols and aromatic amines in flow injection using novel plant peroxidases. 966 27

Glucose and sucrose were measured with an amperometric method by using the flow injection analysis technique. A carbon paste electrode with a renewable surface containing glucose oxidase, horseradish peroxidase, and ferrocene was used in combination with the soluble enzymes invertase and mutarotase. The effect of invertase, mutarotase, and ascorbic acid on the electrode response was examined. Glucose and sucrose concentrations were determined with < 3% errors. The proposed method for glucose and sucrose measurements was validated in real samples of fruit juices. The results were also compared with those obtained with the ultraviolet method.
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PMID:Biosensor for determination of glucose and sucrose in fruit juices by flow injection analysis. 1120 61