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 Oxi/Ferm test system was evaluated for accuracy and reliability for identification of nonfermentative and oxidase-positive fermentative bacteria by using 375 bacterial strains obtained from stock culture and clinical specimens. The Oxi/Ferm system is a compartmentalized tube containing eight media to provide nine biochemical test results. When combined with the oxidase test, the results corresponding to the positive reactions are totaled and the composite number is located in the coding manual to identify the organisms. The 375 isolates studied were evaluated for accuracy of identification, using both the original and revised code manuals. In comparison with the conventional media used, there was 100% correlation in tests for hydrogen sulfide and indole production, over 96% for nitrogen gas, arginine, and urease, over 92% for xylose and dextrose oxidation, and less than 90% for citrate utilization and dextrose fermentation. There was an overall accuracy in identification of 89.3% using the original manual, with accuracy revised slightly upward to 90.7% using the revised manual. There was 100% accuracy in identification with 44.0% of the strains tested (11 species) using the original manual and with 66.1% (16 species) using the revised manual. Thirteen of the 40 original misidentifications and 14 of 35 revised misidentifications resulted from failure to code and were unidentifiable by Oxi/Ferm. The remainder were incorrectly identified or could not be differentiated from closely related strains. Eleven strains of Alcaligenes odorans were correctly identified using the original code, whereas no code was provided in the revised manual. The Oxi/Ferm system is both simple and rapid and is satisfactory for identification of the more common isolates.
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PMID:Evaluation of the oxi/ferm tube system with selected Gram-negative bacteria. 33 24

Uninduced cultures of Saccharomyces cerevisiae exhibit high basal levels of allantoinase, allantoicase, and ureidoglycolate hydrolase, the enzymes responsible for degrading allantoin to urea. As a result, these activities increase only 4- to 8-fold upon induction, whereas the urea-degrading enzymes, urea carboxylase and allophanate hydrolase, have very low basal levels and routinely increase 30-fold on induction. Differences in the inducibility of these five enzymes were somewhat surprising because they are all part of the same pathway and have the same inducer, allophanate. Our current studies reconcile these observations. S. cerevisiae normally contained up to 1 mM allantoin sequestered in a cellular organelle, most likely the vacuole. Separation of the large amounts of allantoin and the enzymes that degrade it provide the cell with an efficient nitrogen reserve. On starvation, sequestered allantoin likely becomes accessible to these degradative enzymes. Because they are already present at high levels, the fact that their inducer is considerably removed from the input allantoin is of little consequence. This suggests that at times metabolite compartmentation may play an equal role with enzyme induction in the regulation of allantoin metabolism. Metabolism of arginine, another sequestered metabolite, must be controlled both by induction of arginase and compartmentation because arginine serves both as a reserve nitrogen source and a precursor of protein synthesis. The latter function precludes the existence of high basal levels of arginase.
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PMID:Metabolite compartmentation in Saccharomyces cerevisiae. 35 30

Pseudomonas aeruginosa AI 3 was able to grow in medium containing acetanilide (N-phenylacetamide) as a carbon source when NH4+ was the nitrogen source but not when urea was the nitrogen source. AIU mutants isolated from strain AI 3 grew on either medium. Urease levels in bacteria grown in the presence of urea were 10-fold lower when NH4+ or acetanilide was also in the medium, but there were no apparent differences in urease or its synthesis between strain AI 3 and mutant AIU 1N. The first metabolic step in the acetanilide utlization is catalyzed by an amidase. Amidases in several AIU strains showed altered physiochemical properties. Urea inhibited amidase in a time-dependent reaction, but the rates of the inhibitory reaction with amidases from the AIU mutants were slower than with AI 3 amidase. The purified amidase from AIU 1N showed a marked difference in its pH/activity profile from that obtained with purified AI 3 amidase. These observations indicate that the ability of strain AIU 1N and the other mutants to grow on acetanilide/urea medium is associated with a mutation in the amidase structural gene; this was confirmed for strain AIU 1N by transduction.
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PMID:Pseudomonas aeruginosa mutants resistant to urea inhibition of growth on acetanilide. 41 Jul 88

Urease activity was found in caecal contents (about 10 mg urea metabolised/g h) and crop contents (about 0-5 mg urea metabolised/g h):there was very low activity in the contents of the colon but none in the rest of the digestive tract. 2. The urease activity of the crop contents was not bacterial in origin but the soyabean meal contained in the diet was found to have comparable activity. 3. Diets low in non-essential nitrogen and based on soyabean, fish meal or fish meal plus 0-2% jack bean urease, did not support higher growth rates when supplemented with urea. 4. The livers of chicks fed on the diet containing fish meal, urea and urease had significantly higher concentrations of free non-essential amino acids than those of chicks fed on the same diet but with urease excluded This suggested that dietary urease affects the availability of ammonia for the synthesis of non-essential amino acids but not for growth.
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PMID:Urease activity in the digestive tract of the chick and its role in the utilisation of urea as a source of non-amino nitrogen. 56 Aug 98

Using the general concept of a dry multilayer analytical element, we can change chemical procedures and configurations to assay several blood components. In the assay of serum urea nitrogen, urease in the reagent layer catalyzes the hydrolysis of urea. A semipermeable membrane excludes aqueous base, but allows ammonia to diffuse to an underlying indicator layer. For the amylase determination, the enzyme hydrolyzes a dyed-starch substrate coated on top of the spreading layer; this produces small fragments, which diffuse to a registration layer. The increase of absorbance at 540 nm is correlated with amylase activity. Bilirubin complexes with a cationic polymer at the interface between the spreading and reagent layers. The direct reading at 460 nm allows determination of total bilirubin in the range 1 to 500 mg/liter. Tirglycerides are hydrolyzed in the spreading layer, and the resulting soluble glycerol readily diffuses into the reagent layer, where it is phosphorylated and subsequently oxidized by glycerophosphate oxidase to yield dihydroxyacetone phosphate and hydrogen peroxide. Peroxidase catalyzes production of a color commensurate with the hydrogen peroxide produced.
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PMID:Multilayer film elements for clinical analysis: applications to representative chemical determinations. 56 6

Urea has been shown to be an obligate intermediate in and the penultimate product of the catabolism of pyrimidine-ring nitrogen in Rhodosporidium toruloides (Rhodotorula). One of a series of mutants selected for its inability to utilize uracil as a sole source of nitrogen was unable to utilize urea also. The mutant accumulated urea and failed to form 14CO2 during supplementation with [2-14C]uracil. Radioautograms from the resulting cell extracts and media failed to reveal expected intermediates. Cell-free extracts of the mutant were shown to lack urease activity. Revertants of the mutant were essentially wild type in all tested attributes. Elements of the reductive pathway for pyrimidine catabolism are present in Rhodosporidium (O. A. Milstein and M. L. Bekker, J. Bacteriol. 127: 1-6, 1976), but is has not been determined whether this pathway is involved with production of urea.
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PMID:Urea: obligate intermediate of pyrimidine-ring catabolism in Rhodosporidium toruloides. 57 31

The present publication is the first of a series on the enzymatic urea tranformation in soil. With about 2,000 pure cultures of micro-organisms it was possible to prove the very good urea utilization by the soil micro-organisms (bacteria, actinomycetes, and fungi). Above all the fungi showed an excellent utilization of urea, while bacteria and actinomycetes were somewhat poorer. Contrary to this is the urease activity of these organisms, and that is the reason why fungi in soil may be regarded as short-time accumulators for urea nitrogen and must not be suppressed by inhibitors.
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PMID:[Contribution to the problem of microbially induced urea transformation in soil. I. On the ability of urea utilization by soil micro-organisms (author's transl)]. 60 75

Pyrolysis gas chromatography (PGC) has been shown to be useful for differentiating enzymes. The enzymes alpha-chymotrypsin, lactate dehydrogenase, catalase, and urease were easily "fingerprinted" on a 1.8 m 0.5% Carbowax 20 M column. Also, in some cases, isoenzymes of lactate dehydrogenase could be distinguished. Based on the pyrolyses of the free aromatic amino acids, four major enzyme pyrolysis peaks were tentatively identified as organic compounds derived from tyrosine and tryptophan. The use of a nitrogen-selective detector in conjunction with the FID and measurement of peak retention times by computer on three different types of columns permitted confirmations of peak identity.
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PMID:Pyrolysis gas chromatography of enzymes. 73 Aug 12

Cell-free extracts prepared from Pseudomonas aeruginosa cells, cultured in a medium containing allantoin as sole nsource of carbon, nitrogen and energy and harvested in the stationary phase, contain an enzymicly inactive allantoinase-inhibitor complex. Pure inhibitor was isolated by dissociation of this complex followed by gelfiltration. The inhibitor had a molecular weight of about 5500 daltons. Association between inhibitor and allantoinase was demonstrated by gelfiltration and by polyacrylamide gel-electrophoresis. The inhibitor was unstable in the absence of 1 M urea and the inactivation was accompanied by aggregate formation and appearance of urease activity. The inhibitor was also isolated from cells containing urease but no allantoinase. It was concluded that the inhibitor is a subunit of urease. Inhibitors isolated from P. aeruginosa and P. acidovorans cells were active against both allantoinase from P. aeruginosa and allantoinase from P. acidovorans.
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PMID:Inactivation of allantoinase from Pseudomonas aeruginosa by a subunit of urease. 82 28

Larvae of the bruchid beetle Caryedes brasiliensis feed exclusively on seeds of the Neotropical legume Dioclea megacarpa, which contains 13 percent L-canavanine by dry weight. L-Canavanine, a nonprotein amino acid analog of L-arginine, exhibits potent insecticidal properties. Most of the seed nitrogen is sequestered in canavanine, and bruchid beetle larvae do not simply excrete this toxic compound. Instead, these larvae possess extraordinarily high urease activity, which facilitates the conversion of canavanine to ammonia through urea. In this way, canavanine is effectively detoxified and a supply of nitrogen for fixation into organic linkage is ensured.
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PMID:Degradation and detoxification of canavanine by a specialized seed predator. 85 40


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