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)

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

The adsorption of 8 enzymes to polyaminomethylstyrene was studied. While lactate dehydrogenase, alkaline phosphatase and glucose-6-phosphate dehydrogenase exhibit a relatively low affinity to the carrier, alcohol dehydrogenase, glutamate dehydrogenase and urease were found to form stabile complexes with the polymer that are enzymatically active. Adsorbed urease and beta-hydroxybutyrate dehydrogenase, are still active after several weeks; the other preparations lose their activity soon. It can be shown by the example of yeast alcohol dehydrogenase that the activity loss following adsorption is caused possibly by a process of reorientation of already bound enzyme molecules or by the increasing enzyme coverage of the carrier, with the active centres becoming more and more inaccessible for the substrate. During the substrate conversion catalysed by the alcohol dehydrogenase-polyaminomethylstyrene complex, a small amount of the enzyme is again detached from the carrier. The activity rises to a certain extent in the supernatant but drops to zero again. The stability of the adsorbed urease is distinctly increased compared with the dissolved enzyme. For the pH optimum and the KM value there are no differences between the two preparations. Continuous application of polyaminomethylstyrene-bound beta-hydroxybutyrate dehydrogenase and urease, respectively, in a column shows that both preparations have unchanged enzymatic activities even after running times of 5 and 24 days, respectively.
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PMID:[Kinetic properties of enzymes in particular of yeast alcohol dehydrogenase following their adsorption on polyaminomethylstyrene]. 102 29

The hydrophobic nature of proteins is characterized by a degree of 2-p-toluidinonaphthalene-6-sulphonate (TNS) affinity to them and is pronounced quantitatively in the semi-saturated (C1/2) concentrations. This index correlates directly with the position of TNS emission maximum after the binding with proteins and reversely with the yield of fluorescence. The preparations of phosphofructokinase, lactate dehydrogenase, xantinoxidase, glyceratekinase, lysozyme, RNase during the long (1-2 h) contact with TNS change the values C1/2, that evidences for interaction with the hydrophobic indicator of new structures of protein molecule or for a change in the nature of its linkage itself. An attempt is made to characterize the accessible for TNS hydrophobic nature of individual proteins by a coefficient of molar hydrophobic nature which unites three mentioned characteristics. Serum albumin, insulin, glucogon, alpha chemotrypsin, DNase are most hydrophobic, pyruvate kinase, aldolase, urease, RNase--least hydrophobic, Glycerate kinase, pyruvate decarboxylase, phosphofructokinase, lactate dehydrogenase, alcohol dehydrogenase, xanthinoxidase, trypsin, lysozyme are in intermediate position.
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PMID:[Comparative characteristics of hydrophobic nature of certain proteins by their interaction with 2-p-toluidinonaphthalene-6-sulfonates]. 120 4

Semipermeable nylon-polyethylenimine artificial cells containing leucine dehydrogenase (EC 1.4.1.9), alcohol dehydrogenase (EC 1.1.1.1), urease (EC 3.5.1.5), and dextran-NAD+ were prepared. Artificial cells could convert ammonia or urea into L-leucine, L-valine, and L-isoleucine. For batch conversion in 20.0 mM of ammonium acetate substrate solutions, in 2 h 0.2 ml of artificial cells could produce 4.48 mumol of L-leucine, 9.98 mumol of L-valine, or 5.96 mumol of L-isoleucine. The corresponding conversion ratios were 22.4, 49.9, and 29.8%. In 20.0 mM of urea substrate solutions, 13.71 mumol of L-leucine, 16.12 mumol of L-valine, or 13.44 mumol of L-isoleucine was produced and the conversion ratios were 68.6, 80.6, and 67.2%. The substrate specificity of leucine dehydrogenase for the reductive amination was determined. Of the three branched-chain amino acids produced, the production rates of L-valine were the highest. The apparent Km values were as follows: 0.32 mM for alpha-ketoisocaproate, 1.63 mM for alpha-ketoisovalerate, and 0.73 mM for Dl-alpha-keto-beta-methyl-n-valerate. The leucine dehydrogenase multienzyme system had a good storage stability. It retained 72.0% of the original activity with artificial cells were stored at 4 degrees C for 6 weeks. The optimum conversion pH and temperature were 8.5-9.0 and 35-40 degrees C. The effects of urea and ammonium salts on conversion rate were also studied. The relative activities in ammonium salts solutions were 45.1-75.9% of those in urea solutions.
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PMID:Conversion of ammonia or urea into essential amino acids, L-leucine, L-valine, and L-isoleucine, using artificial cells containing an immobilized multienzyme system and dextran-NAD+. 2. Yeast alcohol dehydrogenase for coenzyme recycling. 169 39

Artificial cells containing leucine dehydrogenase (EC 1.4.1.9), alcohol dehydrogenase (EC 1.1.1.1; or glucose dehydrogenase, EC 1.1.1.47; or lactic dehydrogenase, EC 1.1.1.27; or malic dehydrogenase, EC 1.1.1.37), urease (EC 3.5.1.5) and dextran-NAD+ were prepared. Ammonia or urea could be converted into L-leucine, L-valine and L-isoleucine using artificial cells with four different multienzyme systems.
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PMID:Conversion of urea or ammonia into essential amino acids (L-leucine, L-valine, and L-isoleucine) using multienzyme systems and NADH-dextran immobilised in artificial cells. 344 45

Benzoyl- and isopentenoyl phosphoric triamides (BPA and IPA) strongly inhibited urease activities from jack bean, soybean, watermelon seed, Proteus mirabilis, P. rettgeri, P. vulgaris, Mycobacterium smegmatis, and Ureaplasma urealyticum. Their I50 values (the final concentration causing 50% inhibition), independent of enzyme source, were 2-21 nM, which are about 1,000-fold lower than that of caprylohydroxamic acid, one of the most potent urease inhibitors. ATP-urea amidolyase activity was inhibited 50% by BPA at a higher concentration of 0.28 mM, but was not affected by IPA even at 1.3 mM. Thirteen kinds of hydrolases (trypsin, chymotrypsin, thermolysin, leucine aminopeptidase, papain, lipase, alpha-amylase, glucuronidase, asparaginase, arylsulfatase, alkaline phosphatase, acid phosphatase, and true cholinesterase), two oxidoreductases (catalase and alcohol dehydrogenase), three transferases (glutamic-oxaloacetic aminotransferase, gamma-glutamyl transpeptidase, and arylsulfotransferase) and two kinases (pyruvate kinase and creatine kinase) were not affected at all even at 1 mM BPA and IPA. Exceptionally, pseudo-cholinesterase from human serum was inhibited by BPA and IPA, whose I50 values were 70 nM and 10 muM, respectively, using acetylthiocholine as a substrate. These values increased to 0.55 muM and 54 muM, respectively, when acetylcholine was used as a substrate. These results show that N-acylphosphoric triamides potently and specifically inhibit urease activity at concentrations of nM order.
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PMID:Specific inhibition of urease by N-acylphosphoric triamides. 384 42

1. Yeast alcohol dehydrogenase was used to determine ethanol in the portal and hepatic veins and in the contents of the alimentary canal of rats given a diet free from ethanol. Measurable amounts of a substance behaving like ethanol were found. Its rate of interaction with yeast alcohol dehydrogenase and its volatility indicate that the substance measured was in fact ethanol. 2. The mean alcohol concentration in the portal blood of normal rats was 0.045mm. In the hepatic vein, inferior vena cava and aorta it was about 15 times lower. 3. The contents of all sections of the alimentary canal contained measurable amounts of ethanol. The highest values (average 3.7mm) were found in the stomach. 4. Infusion of pyrazole (an inhibitor of alcohol dehydrogenase) raised the alcohol concentration in the portal vein 10-fold and almost removed the difference between portal and hepatic venous blood. 5. Addition of antibiotics to the food diminished the ethanol concentration of the portal blood to less than one-quarter and that of the stomach contents to less than one-fortieth. 6. The concentration of alcohol in the alimentary canal and in the portal blood of germ-free rats was much decreased, to less than one-tenth in the alimentary canal and to one-third in the portal blood, but detectable quantities remained. These are likely to arise from acetaldehyde formed by the normal pathways of degradation of threonine, deoxyribose phosphate and beta-alanine. 7. The results indicate that significant amounts of alcohol are normally formed in the gastro-intestinal tract. The alcohol is absorbed into the circulation and almost quantitatively removed by the liver. Thus the function, or a major function, of liver alcohol dehydrogenase is the detoxication of ethanol normally present. 8. The alcohol concentration in the stomach of alloxan-diabetic rats was increased about 8-fold. 9. The activity of liver alcohol dehydrogenase is generally lower in carnivores than in herbivores and omnivores, but there is no strict parallelism between the capacity of liver alcohol dehydrogenase and dietary habit. 10. The activity of alcohol dehydrogenase of gastric mucosa was much decreased in two out of the three germ-free rats tested. This is taken to indicate that the enzyme, like gastric urease, may be of microbial origin. 11. When the body was flooded with ethanol by the addition of 10% ethanol to the drinking water the alcohol concentration in the portal vein rose to 15mm and only a few percent of the incoming ethanol was cleared by the liver.
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PMID:The physiological role of liver alcohol dehydrogenase. 548 98

The pathogenesis of gastric carcinoma developing after infection with Helicobacter pylori now seems to be clear. The release of urease, alcohol dehydrogenase, enzymes and cytotoxin on the one hand, and chemotactic factors, PAF and heat-shock proteins on the other trigger chronic inflammation and epithelial metaplasia and dysplasia in the stomach. Under the influence of additional carcinogens, the epithelial changes progress to severe dysplasia and finally carcinoma. As a result of chronic inflammation, MALT lymphomas can also be induced. These can be made to regress by eradicating Hp. The possibility of being able to prevent up to 80% of the carcinomas of the stomach by eradicating Hp holds out good prospects, over the long-term, for the prevention of these tumors. Accurate identification of the patient groups carrying a high risk is now necessary.
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PMID:[MALT lymphoma, stomach carcinoma--role of Helicobacter pylori. Are chances for prevention on the horizon?]. 784 83

Helicobacter pylori exhibits a complex system of enzymes which serve a range of functions, such as colonization, damage of the host epithelium and provision of essential metabolic substrates. Colonization is favoured by urease and by the action on mucus and the mucosal barrier exerted by phospholipases and proteases, although this latter mechanism is controversial. Toxic effects are effected by urease, alcohol dehydrogenase (ADH), phospholipases and proteolytic enzymes. ADH produces acetaldehyde that is toxic to the mucosal cells, while phospholipases induce generation of products such as lysolecithin, which damage the gastric epithelium. Catalase and sodium dismutase of H. pylori are mainly involved in transforming toxic oxygen metabolites to harmless water; they protect the bacterium from the killing effect of neutrophils. Metabolic enzymes (for example, phosphatases, ATPases) are essential for the generation of energy, for synthesis and transport of cell products and for ion fluxes. In addition, they influence cell growth and the expression of virulence factors.
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PMID:Helicobacter pylori enzymes. 873 Feb 61

Helicobacter pylori colonises the stomach of man and induces a strong mucosal inflammation and a local and systemic immune response. Differences in virulence characteristics of Helicobacter pylori isolates can account for different clinical outcomes of infection. Most determinants of Helicobacter pylori pathogenicity factors are present in all isolates examined; some are present only in or expressed more intensively by certain strains. Many enzymes, i.e., urease, mucinase, phospholipases, alcohol dehydrogenase, neuraminidase, etc. could promote tissue erosion and ulceration by destroying the integrity of mucous, by inducing lipid peroxidation, etc. Strains which express the vacuolating toxin VacA and the associated protein CagA are called Type I and are considered endowed with increased ulcerogenic and inflammatory potential. Type I Helicobacter pylori strains carry a 40 kb genomic fragment called cag which is absent in Type II strains (VacA and CagA negative), and which contains numerous genes encoding for protein homologues to virulence factors expressed by other bacterial pathogens. CagA positive strains are more likely to be isolated from patients with duodenal ulcer and other severe digestive diseases. A simple serological test can help to detect patients at increased risk of developing severe gastroduodenal diseases, which can, therefore, possibly be prevented.
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PMID:Are Helicobacter pylori differences important in the development of Helicobacter pylori-related diseases? 947 94


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