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 activity of the complete arginine pathway-urea cycle was assessed in intact plant cells by employing the commercial enzymes arginase (EC 3.5.3.1) and urease (EC 3.5.1.5) to determine the amount of NaH14CO3 incorporated into [guanido-14C]arginine and/or into [14C]urea during a 3-h labeling period. Recovery of [guanido-14C]arginine was linear from 5 to 1000 nmol/g tissue and averaged 80 +/- 5% (mean +/- SE, N = 3). The procedure is reliable, inexpensive, well suited to the simultaneous analysis of numerous samples, and significantly more sensitive than existing methods. The method is ideally suited for assessing the activity of the complete arginine biosynthetic pathway in intact cells. In addition, the method has the distinct advantage of providing simultaneous measurement of the amount of NaH14CO3 accumulating in arginine relative to the amount accumulating as urea. Evidence is presented demonstrating that both the activity of the arginine pathway and the relative amounts of [guanido-14C]arginine and [14C]urea synthesized from NaH14CO3 were influenced by changes in the level of ornithine, NH+4, or phosphorus available to plant tissues.
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PMID:Application of commercial enzymes to measure the activity of the arginine pathway-urea cycle in intact cells. 609 59

The results of the study of 65 Brucella strains isolated from myomorphous rodents in the Northern Caucasus are presented. The study was made with the aim of finding out additional characteristics for the identification of these strains. Using the main tests recommended by the FAO/WHO Subcommittee on the Taxonomy of Brucella, as well as some additional tests, we have revealed that the strains under study are very similar to B. suis. At the same time their capacity for agglutination with anti-melitensis monospecific serum, their high sensitivity to pyronin B, safranine T and gentian violet, their low urease activity and their oxidizing activity in respect to L-alanine, L-asparagine, L-glutamic acid, L-arginine, DL-ornithine, DL-citrullin and L-livin make it possible to consider them the fifth independent biotype of B. suis.
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PMID:[Taxonomy and ecology of brucellosis pathogens isolated from Muridae in the northern foothills of the Caucasus mountains. I. Cultural and biochemical properties of Brucella isolated from Muridae]. 622 76

Arginine is rapidly depleted from the medium during the cultivation of T. vaginalis in a defined or semi-defined medium. It is broken down to ornithine, ammonia and carbon dioxide by the three enzymes of the dihydrolase pathway: arginine deiminase, catabolic ornithine carbamyltransferase (OCTase) and carbamate kinase. Arginase and urease as well as citrulline hydrolase appear to be absent. Ornithine, a product of the pathway was further converted to putrescine by an active ornithine decarboxylase. Apparent substrate Km values determined were arginine deiminase, 103 microM; catabolic OCTase, 71 microM; ornithine decarboxylase 134 microM. A substrate level phosphorylation is associated with the pathway; the significance of this to the overall energy economy of the cell is unclear.
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PMID:The pathway of arginine catabolism in the parasitic flagellate Trichomonas vaginalis. 631 11

Even 70 years ago Gram-negative coccobacilli had been recognized in vaginal discharge and were cultured 30 years ago. The need to have blood in agar medium for cultivation suggested that the organisms might be a Haemophilus species. Later, however, growth characteristics and other features resulted in their being placed in the genus Corynebacterium, before it was realized that this was inappropriate and they were transferred to a new genus and species Gardnerella vaginalis. The organisms are Gram-variable, non-sporing, non-flagellate, non-motile coccobacilli of average size 0.4 X 1-1.5 microns. The cell wall is laminated and some strains possess pili. G. vaginalis is fermentative and dextrose, fructose, galactose, glucose, maltose, mannose, ribose and starch are most likely to be metabolized. However, published patterns of the sugars fermented vary widely and most workers do not rely on such tests as a means of identification. Of many other features exhibited by G. vaginalis, the following are outstanding: it does not produce catalase, cytochrome oxidase, hydrogen sulphide, indole, or urease. Nor does it degrade aesculin, liquefy gelatin, reduce nitrate, or decarboxylate arginine, lysine or ornithine. On the other hand, it is sensitive to hydrogen peroxide, often causes beta-haemolysis and usually hydrolyses hippurate and starch. G. vaginalis is serologically heterogeneous and causes haemagglutination which is mannose resistant. It is resistant to several antibiotics, including amphotericin, colistin, nalidixic acid and gentamicin, which may be incorporated in selective media.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The bacteriology of Gardnerella vaginalis. 639 9

Flurofamide, a potent inhibitor of urease, at concentrations of 0.0007 to 0.001 mg/l inhibited the multiplication of three ureaplasma strains of human genital origin (one tetracycline-resistant) and two and three strains of marmoset genital and oral origin, respectively. However, a more than 1000-fold greater concentration of the drug was required to kill the organisms. Flurofamide did not inhibit the growth of arginine-hydrolysing or glucose-fermenting mycoplasmas, indicating its specificity for ureaplasmas. When it was given orally in a dose of 25 mg twice on one day and 25 mg on one further day to marmosets infected naturally with ureaplasmas in their throats, the organisms disappeared rapidly. The animals remained ureaplasma-free for 42 to 106 days, at which time they were successfully infected experimentally.
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PMID:The inhibitory effect of flurofamide on ureaplasmas and their elimination from marmosets by its use. 644 Aug 84

The energy requirements for the uptake and retention of arginine by vacuoles of Neurospora crassa have been studied. Exponentially growing mycelial cultures were treated with inhibitors of respiration or glycolysis or an uncoupler of respiration. Catabolism of arginine was monitored as urea production in urease-less strains. The rationale was that the rate and extent of such catabolism was indicative of the cytosolic arginine concentration. No catabolism was observed in cultures treated with an inhibitor or an uncoupler of respiration, but cultures treated with inhibitors of glycolysis rapidly degraded arginine. These differences could not be accounted for by alterations in the level or activity of arginase. Mycelia growing in arginine-supplemented medium and treated with an inhibitor or uncoupler of respiration degraded an amount of arginine equivalent to the cytosolic fraction of the arginine pool. The inhibitors and the uncoupler of respiration reduced the ATP pool and the energy charge. The inhibitors of glycolysis reduced the ATP pool but did not affect the energy charge. The results suggest that metabolic energy is required for the transport of arginine into the vacuoles but not for its retention. The latter is affected by inhibitors of glycolysis. The form of energy and the nature of the vacuolar transport mechanism(s) are discussed.
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PMID:Energetics of vacuolar compartmentation of arginine in Neurospora crassa. 646 34

This study was conducted to study chemically and serologically the characteristics of the Ureaplasmas isolated from the human oral cavity. Two hundred and fifty-one healthy and 12 periodontitis subjects were examined for the incidence of the isolation of Ureaplasmas from their oral cavity. A total of twenty-six strains was isolated from the healthy human saliva. But no strains could be isolated from a variety of clinical specimens obtained from the patients. The serological properties of the isolates were tested by the method of metabolism inhibition test (MI test). Seven out of 26 isolates were serologically identical with either one of the ATCC standard strains. However, the serological types of the other strains could not be demonstrated by the MI test. The biological characteristics of 4 isolates and ATCC strains were tested by the usual method. The isolates did not metabolize glucose and arginine, while all strains hydrolyzed urea. On the other hand, none of the isolates lysed skimmed milk and gelatin. The proteolytic activity of the isolates could be demonstrated by using casein and horse serum proteins as substrates. Zymogram patterns from one of the isolates and Streptococcus salivarius were obtained by polyacrylamide gel electrophoresis of the cells lysed with digitonin or cell protein extracts. On the basis of the gel electrophoresis patterns, it is clear that the urease of the Ureaplasma is different from that of the Streptococcus salivarius.
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PMID:Biochemical and serological studies on oral ureaplasma. 659 16

Recent studies have indicated that viral infections, aspirin treatment and hyperammonemia are associated with Reye's syndrome. It has also been reported that free fatty acids in serum and total lipids in the liver of Reye's syndrome patients are elevated during illness. The role of the lipid changes in the development of the disorder cannot be optimally studied in human patients, because infection and aspirin ingestion occur prior to the earliest symptoms of Reye's syndrome. Effects of influenza B infection, aspirin treatment and hyperammonemia on the level of free fatty acids, total lipids and triacylglycerols in serum and liver of an animal model of Reye's syndrome are reported here. Hyperammonemia was produced in young, male ferrets either by feeding them small amounts of an arginine-deficient diet after overnight fasting or by an intraperitoneal injection of jackbean urease. The ferret model resembled Reye's syndrome in developing increased levels of individual and total serum free fatty acids, liver triacylglycerol and total lipids. The results also indicate that influenza infection or aspirin treatment, or both, while increasing the severity of encephalopathy in the deficient ferrets, did not cause a significant change in the level of serum free fatty acids. Other results suggest that elevation of serum ammonia, serum free fatty acid or liver lipids, either singly or in various combinations, does not provide conditions that can explain the rapidly developing encephalopathy in the arginine-deficient ferrets.
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PMID:Free fatty acids in an animal model of Reye's syndrome. 661 53

Lenses produce both ammonia and urea, and a previous report suggested that bovine lenses contain a complete urea cycle capable of synthesizing urea from bicarbonate and ammonia. To determine whether lenses produce urea by a complete urea cycle or by arginase alone, intact lenses were cultured with [guanido-14C]-arginine or [14C]-bicarbonate. The [14C]-urea was volatilized to [14C]-CO2 by urease and collected in KOH. The cultured rat, bovine and human lenses produced [14C]-urea from [14C]-arginine; therefore lens arginase activity was also examined in homogenates of rat and human lenses. Rat lens homogenates had constant arginase activity for at least 2 hr at 37 degrees C, and activity increased linearly with the concentration of lens homogenate. Rat lens arginase had an apparent Vmax of approximately 13 nmol/hr/mg lens wet weight in lens homogenates and produced 4-6 nmol urea/hr/mg at 25 mM arginine. Human lens homogenates produced 1-5 nmol/hr/mg. In contrast, neither bovine nor rat lenses cultured with [14C]-bicarbonate produced detectable [14C]-urea, although label was incorporated into unidentified nonvolatile products. These products were shown by ion exchange chromatography and enzymatic assay to contain no detectable arginine or urea. It was concluded that although arginase activity is present, neither rat nor bovine lenses contain significant urea cycle activity. However, it is possible that arginase serves as a source of lens ornithine.
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PMID:Urea formation in rat, bovine, and human lens. 666 5

A small, fastidious gram-negative anaerobe was isolated from men with non-gonococcal urethritis (NGU). The isolates are described as NGU-associated anaerobes because they were extremely rare in men with urethritis other than NGU, and in asymptomatic men. They showed twitching motility, had many polar pili and appeared to be a homogenous group culturally, morphologically and biochemically. None of the strains fermented or utilised carbohydrates or organic acids as sole sources of carbon for energy and growth. However, growth of all strains was stimulated by formate and fumarate in liquid and solid media, especially in the former where growth seemed dependent on these growth factors. Unlike most anaerobes they produced cytochrome enzyme(s) that might be involved in oxidation-reduction reactions in the presence of oxygen as some of the strains were capable of growing in 5% oxygen. However, growth and energy generally resulted from anaerobic phosphorylation. Strains of this anaerobe seemed to require a low redox-potential (Eh) for survival during transportation but this was not essential for growth. Comparative studies with the other asaccharolytic anaerobes showed some similarity between the NGU-associated anaerobe, Bacteroides ureolyticus and Wolinella succinogenes. Like these, some NGU-associated strains pitted agar media and all produced urease. However, unlike these anaerobes, strains of the NGU-associated anaerobe produced enzymes for the hydrolysis of arginine, and the decarboxylation of lysine and ornithine. They also produced oxidase and some strains haemolysed sheep red cells. However, lactic acid was not an end-product of the metabolism of glucose by any of the strains. The NGU-associated anaerobes are strikingly different from anaerobic vibrios, B. praeacutus and B. asaccharolyticus.
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PMID:Characteristics of a gram-negative anaerobe isolated from men with non-gonococcal urethritis. 670 82


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