Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:6.3.4.6 (urease)
7,490 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The yeast "H" of the genus Candida guilliermondii can grow on hydrocarbons as the only source for carbon. Urea can serve as a nitrogen source for this yeast which lacks detectable urease activity. During urea metabolism ammonia has never been accumulated in the culture medium. However, transferring the yeast from complete urea-medium into an urea containing phophate-buffer, the degradation of urea continues and ammonia is accumulated as well as CO2 evolved. In cell-free extracts of the yeast urea amidolyase activity was detected in the presence of ATP, biotin and specific cations. Obviously, the synthesis of urea amidolyase is induced by urea and arginine and repressed by the catabolite ammonia. Similarly the synthesis of arginase is regulated by arginine and ammonia. The analytical data of the arginase action differ significantly in relation to the carbon source of the culture medium. Both the level of arginase and ornithine carbamyl-transferase change in a characteristic way during the batch-culture. From the lower level of arginase in relation to ornithine carbamyltransferase it can be concluded that especially in alkane-metabolizing yeast the arginine catabolism is not very intensive.
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PMID:[Anabolic and catabolic enzymes of urea metabolism in a carbohydrate-utilizing strain of Candida guilliermondii]. 2 24

The catabolic products of arginine metabolism were observed in Aphanocapsa 6308, a unicellular cyanobacterium, by thin layer chromatography of growth media, by limiting growth conditions, and by enzymatic analysis. Of the organic, nitrogenous compounds examined, only arginine supported growth in CO2-free media. The excretion of ornithine at a concentration level greater than citrulline suggested the existence in Aphanocapsa 6308 of the arginine dihydrolase pathway which produced ornithine, CO2,NH4,+ adenosine 5'-triphosphate. Its existence was confirmed by enzymatic analysis. Although cells could not grow on urea as a sole carbon source a very active urease and subsequently an arginase were also demonstrated, indicating that Aphanocapsa can metabolize arginine via the arginase pathway. The level of enzymes for both pathways indicates a lack of genetic control. It is suggested that the arginase pathway provides only nitrogen for the cells wheras the arginine dihydrolase pathway provides not only nitrogen, but also CO2 and adenosine 5'-triphosphate.
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PMID:Arginine catabolism in Aphanocapsa 6308. 10 70

By counting the volatile molecules produced by an immobilized-enzyme catalyzed reaction which is interfaced to a mass spectrometer via a semi-permeable membrane, a general approach to biochemical measurement and detection is obtained which offers the potential of high sensitivity, specificity and speed. In combination with molecule microscopy, this method should allow, for example, a mapping of suitable enzyme distributions in non-stained and non-fixed tissue slices. Immobilized urease (urea amidohyrdrolase, EC 3.5.1.5) was used to assay urea using CO2 as the volatile product, and alcohol dehydrogenase (alcohol:NAD+ oxidoreductase, EC 1.1.1.1) was used to assay NADH using ethanol as the volatile product.
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PMID:Biochemical assay by immobilized enzymes and a mass spectrometer. 18 Oct 86

We used a differential thermal detector in conjunction with an immobilized urease reactor to determine urea in serum. Samples (120 mul) are introduced into a flow stream and passed through an "adiabatic" column, which is packed with enough insolubilized urease to completely convert urea to ammonia and carbon dioxide. Measured temperature changes are directly proportional to the serum urea concentration. Urea in the presence of protein, bilirubin, and hemoglobin can thus be rapidly, simply, and inexpensively measured. Results correlate well with those obtained by the manual diacetyl monoxime and urease/indophenol methods.
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PMID:Rapid-flow enthalpimetric determination of urea in serum, with use of an immobilized urease reactor. 94 41

In field experiments wheat in the phase of shooting was sprayed with solutions of chlorocholinechloride (CCC) and urea, CCC and ammonium salt MCPA (Aminex) or CCC, urea and Aminex. The effect of the treatment on dry weight of overground parts of wheat, number of bacteria, production of carbon dioxide, urease activity and content of ammonium in the rhizosphere soil was investigated. In all cases evolution of carbon dioxide in the rhizosphere soil was higher than that in the control soil. Highest numbers of bacteria were found in the rhizosphere soil of plants treated with urea, the herbicide and their mixtures. Content of ammonium was higher in the control soil than in the rhizosphere soils, the urease activity was highest in the rhizosphere soil of plants treated with the solution of the herbicide and with the combination of the herbicide with urea.
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PMID:Biological changes in the rhizosphere of wheat after foliar application of chlorocholinechloride, urea and 4-chloro-2-methylphenoxyacetic acid. 119 93

Actinomyces viscosus is a gram-positive, non-acid-fact, facultative, catalase-positive, filamentous, or diphtheroidal microorganism. It was isolated from six canine infections during a period of 1.5 years. The organism was cultured from exudate and flaky granules aspirated from infectious granulomas and empyemas. All cultures grew well aerobically and anaerobically with the addition of 10% carbon dioxide. They fermented lactose, produced catalase and acetylmethylcarbinol, reduced nitrates, hydrolyzed aesculin, and did not produce gelatinase or urease. These physiological characteristics distinguish A. viscosus from other morphologically similar organisms.
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PMID:Identification of Actinomyces viscosus from canine infections. 123 70

New methods for the determination of L-asparagine and arginine are described. Solutions containing L-asparagine were pumped through an asparaginase tube, which catalyzed the hydrolysis of L-asparagine to L-aspartis acid and ammonium ion. For L-arginine determination, solutions containing L-arginine were pumped through an arginase-urease tube. This dual enzyme tube catalyzed the conversion of L-arginine to L-ornithine, carbon dioxide, and ammonium ion. The ammonium ion concentrations in the effluent of the enzyme tubes were determined quantitatively by an ammounin-ion-selective electrode. The potentiometric response of the electrode was directly proportional to the logarithm of the concentration of L-asparagine and L-arginine in the range of 0.1-50 mM. An equation relating the electrode response and the substrate concentration is derived.
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PMID:Reagentless determination of L-asparagine and L-arginine via the combined use of immobilized enzymes and an ion-selective electrode. 125 83

Two urease-based tests--the urease slide test and the radiolabeled urea breath test, are commonly used for the diagnosis of Helicobacter pylori infection of the stomach. The reliability of these tests in chronic uremia was compared with serological tests for H pylori antibodies, and with direct detection of the organism by microscopy or culture of gastric antral biopsies. Twenty-seven patients with chronic renal failure and dyspepsia underwent upper gastrointestinal endoscopy. Twelve of these patients (46%) were judged to be infected with H pylori on the basis of identification of the organism on microscopy or culture of antral biopsy. Both urease-based tests were able to determine H pylori status, despite the markedly increased concentrations of urea in the gastric juice found in chronic renal failure. The urease slide test performed on antral biopsies obtained at endoscopy proved reliable in determining H pylori status with no false-positive nor false-negative results after 20 minutes and 24 hours of incubation. The 14C-urea breath test also differentiated the infected from the uninfected patients. The 20-minute 14CO2 excretion (kg %dose/mmol CO2 x 100) ranged from 50 to 834 in the H pylori-infected patients, compared with 0.3 to 27 in the H pylori-noninfected patients (P < 0.0001); the 90-minute values ranged from 88 to 398 in the former, compared with 1 to 79 in the latter (P < 0.0001). The excretion of 14CO2 (derived from bacterial hydrolysis of ingested 14C-urea) was higher in all the uremic patients compared with nonuremic controls, and in half of the H pylori-noninfected uremic patients there was a late increase in 14CO2 excretion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The diagnosis of Helicobacter pylori infection in uremic patients. 146 85

The 100 ml of canal water samples of 36 canals in Bangkok Metropolitan Area were examined in three periods starting from July-September 1988, November 1988-January 1989 and February-April 1989. Each time the 52 water samples were checked. Of 156 water samples, 116 strains of Campylobacter species were isolated. They were 63.79 per cent (74 strains) of C. cryaerophila and 36.21 per cent (42 strains) of C. cryaerophila-like organisms. The differentiation was determined by urease activity test. C. cryaerophila was isolated from 44.23 per cent (23 strains), 51.19 per cent (27 strains) and 46.15 per cent (24 strains) and also C. cryaerophila-like organism from 28.85 per cent (15 strains), 19.23 per cent (10 strains) and 32.69 per cent (17 strains) of the 52 samples during each period respectively. Since C. cryaerophila and C. cryaerophila-like are aerotolerant Campylobacter, they grow well in aerobic conditions at 25 degrees-36 degrees C. On the contrary, thermophilic Campylobacter such as C. jejuni, C. coli and C. laridis require atmosphere containing 5 per cent O2, 10 per cent CO2, 85 per cent N2 and temperature at 36 degrees-42 degrees C, so the environment in the canals is unfavorable for their growth. The etiological role of C. cryaerophila in pathogenesis in humans is still unknown, and requires furthers study. This study shows that canals can be an important source of these two Campylobacter species that might be potential pathogens in the future.
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PMID:Isolation of Campylobacters from the canals of Bangkok metropolitan area. 148 83

A noninvasive test for the detection of Helicobacter pylori infection that uses [15N]urea as a tracer has been established. The principle the test is based on is the strong urease activity of H. pylori. After oral ingestion, [15N]urea is broken down into ammonia and carbon dioxide by H. pylori urease in the stomach. The ammonia is absorbed into the blood and excreted in the urine. The amount of [15N]urea, reflecting the magnitude of H. pylori infection, is evaluated by measuring the abundance and excretion rate of 15N in ammonia in the urine. Thirty-six patients were examined in our study. The 15N excretion rates in urine ammonia of patients who were H. pylori positive were significantly higher than those of H. pylori-negative patients (P less than 0.05). Twenty-three patients were H. pylori positive by Gram stain and culture. The sensitivity of the 15NH4 excretion test compared with these techniques was 96%, and no false positives were obtained. The 15NH4+ excretion rates of 13 H. pylori-negative subjects were all in the normal range (less than 0.3%). This method is a simple, precise, highly sensitive, noninvasive, nonradioactive test. It could be used for diagnosis as well as for the followup of patients receiving H. pylori eradication therapy, especially children and pregnant women. It could also be used in epidemiological investigation of H. pylori infection in a general population.
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PMID:15NH4+ excretion test: a new method for detection of Helicobacter pylori infection. 173 51


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