Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.1.5 (urease)
 7,257 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Citrate isocitrate and 2-oxoglutarate levels were determined in isolated rat hepatocytes and in particulate and soluble fractions, thereof, obtained by the digitonin and silicone oil fractionation technique. 2. Caculated from isocitrate/2-oxoglutarate ratios ("indicator metabolite method"), the redox potential of mitochondrial free NADPH is -402 mV, whereas that of the extramitochondrial (cytosolic) space is about 10 mV more positive, -392 mV. 3; Addition of ammonia (either as ammonium chloride or from urea plus urease) to isolated hepatocytes causes preferential oxidation of mitochondrial NADPH, is demonstrated by spectrophotometry of the dihydro band and by the changes in the isocitrate/2-oxoglutarate ratios. The redox potential difference of free NADPH between mitochondria and cytosol is abolished or even reserved. 4. It is concluded that during urogenesis from ammonia mitochondrial isocitrate oxidation is shifted largely in favor of the NADP-linked as opposed to the NAD-linked enzyme; isocitrate concentration under these conditions is less than 10 muM, below the Km (isocitrate) of the NAD-linked enzyme but in the range of that for the NADP-linked enzyme. 5. Both in the absence and in the presence of ammonia there is a concentration gradient across the mitochondrial inner membrane (from mitochondria to cytosol) for citrate, isocitrate, and also, to a smaller extent, for 2-oxoglutarate. 6. These results and data in the literature on enzyme activity are in agreement with the assumption of near-equilibrium of NADP-dependent isocitrate dehydrogenases in the mitochondrial matrix and cytosolic spaces in the absence of ammonia; accordingly, during urea formation from added ammonia the redox potential of mitochondrial free NADPH is increased to -391 mV or possibly even higher if there exists an indicator error under this condition.
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PMID:Mitochondrial and cytosolic NADPH systems and isocitrate dehydrogenase indicator metabolites during ureogensis from ammonia in isolated rat hepatocytes. 1 98

The potential of sand as a support for immobilized enzymes was investigated by preparing alkylamine sand and devising methods to measure the total number of amine groups present and the fraction available for immobilization of enzymes. Alcohol dehydrogenase (alcohol: NAD oxidoreductase, EC 1.1.1.1.) and lactate dehydrogenase (L-lactate:NAD oxidoreductase, EC 1.1.1.27) were immobilized on alkylamine sand, and the stability of the immobilized protein and dehydrogenase activity was measured. Urease (urea amidohydrolase, EC 3.5.1.5) was also immobilized on sand to test the applicability of these methods to larger scale immobilizations. Results suggest that sand shows promise as a support for immobilized enzymes.
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PMID:Characterization of sand as a support for immobilized enzymes. 17 87

A direct enzymatic micromethod (sample volume, 3mul) has been adapted to the centrifugal analyzer (ENI-GEMSAEC) for measurement of urea in plasma and urine. The method is based on urease (urea amidohydrolase, EC3.5.1.5)/glutamate dehydrogenase [l-glutamate:NAD(P)+oxidoreductase (deaminating), EC1.41.3] coupled reactions, and uses a two-point fixed-time (t(1)=20s,t(2)=50s)kinetic scheme for monitoring the rate of comsumption of NADH at 340 nm. Sensitivity and precision of the method are excellent,and results compare well with those from a commonly used continuous-flow method.
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PMID:Direct enzymatic determination of urea in plasma and urine with a centrifugal analyzer. 97 5

A total of 307 lungs obtained from a slaughterhouse were cultured by a dilution technique for the isolation of Haemophilus spp. The technique consisted of performing serial (10-fold) dilutions of the tissue samples to a dilution of 10(-5). Two selective media were used. L broth consisted of a basal brain heart infusion broth containing 5% horse serum, 5% yeast extract, and 100 micrograms of NAD and 0.5 microgram of lincomycin per ml. L-B broth was identical to L broth, except 1.5 microgram of bacitracin per ml was included. The broths were incubated overnight and then plated onto blood agar. A total of 83 (27%) isolates were obtained, and both media proved to be necessary, as a proportion of isolates grew in one of the media employed but not in the other. Of the isolates, 66.3% were urease positive and most of these (98%) were classified as "minor group" strains. Urease-negative strains (27.7%) were classified as Haemophilus parasuis.
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PMID:Dilution technique for isolation of Haemophilus from swine lungs collected at slaughter. 635 Mar 43

Thirty Haemophilus strains and six Actinobacillus strains, all of porcine origin, were examined for their biochemical reactivity on API 20E and API ZYM test strips using dense cell suspensions (supplemented with NAD as appropriate) as strip inocula. When combined with a test for V-factor dependency, the use of both strips allowed adequate differentiation of closely related organisms. Numerical taxonomic analysis of the data demonstrated that the majority of the haemophili and actinobacilli studied could be placed in one of four major clusters; these clusters contained, respectively, the H. pleuropneumoniae--A. pleuropneumoniae strains, the H. parasuis strains, strains belonging to Haemophilus taxon "minor group," and strains belonging to an unusual group of mannitol-positive, urease-negative haemophili. A representative of Haemophilus species taxon C and an unusual Actinobacillus isolate appeared to be comparatively unrelated to organisms in the four major clusters. Although it may, on occasion, be difficult to place an unusual isolate in any one particular group, owing to the uncertain taxonomy of some of these organisms, it is concluded that API test strips can serve as useful tools for the characterization and differentiation of porcine haemophili and actinobacilli.
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PMID:Porcine haemophili and actinobacilli: characterization by means of API test strips and possible taxonomic implications. 650 90

The enzymic mechanism of metabolization of urea-formaldehyde condensation products (methyleneureas; MU) and the fate of the degradation products ammonium, urea and formaldehyde were studied in bacteria isolated from garden soil, which were able to use methyleneureas as the sole source of nitrogen for growth. An organism identified as Ochrobactrum anthropi completely degraded methylenediurea (MDU) and dimethylenetriurea (DMTU) to urea, ammonia, formaldehyde and carbon dioxide. An enzyme designated as methylenediurease (methylenediurea deiminase; MDUase) was responsible for the degradation of both MDU and DMTU as well as higher polymerized MU. Growth on MU as the nitrogen source specifically induced the synthesis of this enzyme, which seems to be located in the periplasm of the bacterium. Under these growth conditions, urease as well as NAD-specific formaldehyde and formiate dehydrogenase were expressed to high levels, efficiently using the products of MU degradation, and high-affinity transport systems for urea and ammonia were synthesized scavenging the environment for these products.
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PMID:Microbial urea-formaldehyde degradation involves a new enzyme, methylenediurease. 1052 91

A bacterial strain utilizing methanol as the sole source of carbon and energy was isolated from the maize phyllosphere. Cells are nonpigmented gram-negative motile rods that do not form spores or prosthecae and reproduce by binary fission. The strain does not require vitamins or supplementary growth factors. It is obligately aerobic and urease-, oxidase-, and catalase-positive. The optimum growth temperature is 35-40 degrees C; the optimum pH is 7.0-7.5. The doubling time is 2 h. The bacterium implements the ribulose monophosphate pathway and possesses NAD(+)-dependent 6-phosphogluconate dehydrogenase and enzymes of the glutamate cycle. alpha-Ketoglutarate dehydrogenase and enzymes of the glyoxylate cycle (isocitrate lyase and malate synthase) are absent. Fatty acids are dominated by palmitic (C16:0) and palmitoleic (C16:1) acids. The major phospholipids are phosphatidylethanolamine, phosphatidylglycerol, and phosphatidylcholine. Cardiolipin is present in minor amounts. The dominant ubiquinone is Q8. The bacterial genome contains genes controlling the synthesis and secretion of cytokinins. The G + C content of DNA is 57.2 mol %, as determined from the DNA thermal denaturation temperature (Tm). The bacterium shows low DNA homology (< 10%) with restricted facultative methylotrophic bacteria of the genus Methylophilus (M. methylotrophus NCIMB 10515T and M. leisingerii VKM B-2013T) and with the obligate methylotrophic bacterium (Methylobacillus glycogenes ATCC 29475T). DNA homology with the type representative of the genus Methylovorus, M. glucosetrophus VKM B-1745T, is high (58%). The new isolate was classified as a new species, Methylovorus mays sp. now.
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PMID:[Methylovorus mays--novel species of aerobic, obligatory methylotrophic bacteria associated with plants]. 1131 76

Urea could be effectively converted into L-glutamic acid with semipermeable nylon-polyethylenimine artificial cells containing L-glutamic dehydrogenase (EC 1.4.1. 3), yeast alcohol dehydrogenase (EC 1.1.1.1), urease (EC 3.5.1. 5) and soluble dextran-NAD(+). For batch conversion, the artificial cell suspension to total reaction volume ratios ranged from 1 in 5 to 1 in 60. From 22.6 to 53.4 micromol of L-glutamic acid could be produced by 0.4 mL artificial cell suspension within 2 h. The corresponding conversion ratios were 56.5-11. 1%. The L-glutamic dehydrogenase multienzyme system showed a good storage stability: 66.0% of the original activity was retained after 1 month of storage at 4 degrees C. A small bioreactor was prepared to contain 4.0 mL artificial cells. At a flow rate of SV = 1.5 h(-1), the maximum conversion rate was 49.6 micromol L-glutamic acid/p h. Thirty-eight percent of the maximum activity was retained when continuously used for four days at 22 degrees C. A kinetic analysis for the L-glutamic dehydrogenase multienzyme system was studied. The Michaelis constants are as follows: alpha-ketoglutarate is 0.838 mM; urea is 1.90 mM; dextran- NAD(+) is 0.345 mM; and ethanol is 5.31 mM.
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PMID:Conversion of alpha-ketoglutarate into L-glutamic acid with urea as ammonium source using multienzyme systems and dextran-NAD+ immobilized by microencapsulation within artificial cells in a bioreactor. 1858 59

We prepared artificial cells each containing leucine dehydrogenase (EC 1.4.1.9), urease (EC 3.5.1.5), soluble dextran-NAD(+), and one of the following coenzyme regenerating dehydrogenases: glucose dehydrogenase (EC 1.1.1.47); yeast alcohol dehydrogenase (EC 1.1.1.1); malate dehydrogenase (EC 1.1.1.37); or lactate dehydrogenase (EC 1.1.1.27). Artificial cells were packed in small columns. L-Leucine, L-valine, and L-isoleucine were continuously produced with simultaneous dextran-NADH regeneration. The maximum production ratios depended on the coenzyme regenerating systems used: 83-93% for D-glucose and glucose dehydrogenase system; 90% for ethanol and yeast alcohol dehydrogenase system; 45-55% for L-malate and malate dehydrogenase system; and 64-78% for L-lactate and lactate dehydrogenase system. Kinetic experiments were also carried out. The apparent K(m) values are as follows: 0.33 mM for alpha-ketoisocaproate (KIC); 0.51 mM for alpha-ketoisovalerate (KIV); 0.58 mM for DL-alpha-keto-beta-methyl-n-valerate (KMV); 3.52 mM for urea; 27.82 mM for D-glucose; 3.89 mM for ethanol; 3.02 mM for L-malate; and 16.67 mM for L-lactate. Kinetic analysis showed that KIC, KIV, and KMV were all competitive inhibitors in the reactions catalyzed by leucine dehydrogenase. Their inhibitor constants were the corresponding K(m) values.
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PMID:Production of essential L-branched-chain amino acids in bioreactors containing artificial cells immobilized multienzyme systems and dextran-NAD+. 1859 77

From early 1989 the emergence of an infectious bacterial disease resembling infectious coryza was seen in several commercial chicken flocks in Natal Province of South Africa. Clinical signs were facial swelling and nasal discharge. An organism was routinely isolated from the infra-orbital sinus or trachea of infected chickens. The organism was found to be a Gram-negative rod, non-motile, V factor (nicotinamide adenine dinucleotide, NAD)-independent, catalase negative, oxidase positive and urease and indole negative. No gas was produced from carbohydrates and acid was produced from glucose, mannitol, inositol and sorbitol. Experimental inoculation of this organism into the infraorbital sinus of SPF chickens and conventional broilers produced an acute upper respiratory disease. The organism could be recovered for up to 7 days post-inoculation. The organism is closely related to Haemophilus paragallinarum, the cause of infectious coryza, but because it is NAD-independent it cannot be classed as an Haemophilus species.
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PMID:An upper respiratory disease of commercial chickens resembling infectious coryza, but caused by a V factor-independent bacterium. 1867 Sep 57


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