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:3.5.1.5 (urease)
7,257 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Soybean (Glycine max [L.] Merrill) mutant aj6 carries a single recessive lesion, aj6, that eliminates ubiquitous urease activity in leaves and callus while retaining normal embryo-specific urease activity. Consistently, aj6/aj6 plants accumulated urea in leaves. In crosses of aj6/aj6 by urease mutants at the Eu1, Eu2, and Eu3 loci, F(1) individuals exhibited wild-type leaf urease activity, and the F(2) segregated urease-negative individuals, demonstrating that aj6 is not an allele at these loci. F(2) of aj6/aj6 crossed with a null mutant lacking the Eu1-encoded embryo-specific urease showed that ubiquitous urease was also inactive in seeds of aj6/aj6. The cross of aj6/aj6 to eu4/eu4, a mutant previously assigned to the ubiquitous urease structural gene (R.S. Torisky, J.D. Griffin, R.L. Yenofsky, J.C. Polacco [1994] Mol Gen Genet 242: 404-414), yielded an F(1) having 22% +/- 11% of wild-type leaf urease activity. Coding sequences for ubiquitous urease were cloned by reverse transcriptase-polymerase chain reaction from wild-type, aj6/aj6, and eu4/eu4 leaf RNA. The ubiquitous urease had an 837-amino acid open reading frame (ORF), 87% identical to the embryo-specific urease. The aj6/aj6 ORF showed an R201C change that cosegregated with the lack of leaf urease activity in a cross against a urease-positive line, whereas the eu4/eu4 ORF showed a G468E change. Heteroallelic interaction in F(2) progeny of aj6/aj6 x eu4/eu4 resulted in partially restored leaf urease activity. These results confirm that aj6/aj6 and eu4/eu4 are mutants affected in the ubiquitous urease structural gene. They also indicate that radical amino acid changes in distinct domains can be partially compensated in the urease heterotrimer.
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PMID:Interallelic complementation at the ubiquitous urease coding locus of soybean. 1291 38

Urease activation is critical to the virulence of many human and animal pathogens. Urease possesses multiple, nickel-containing active sites, and UreE, the only nickel-binding protein among the urease accessory proteins, activates urease by transporting nickel ions. We performed NMR experiments to investigate the solution structure and the nickel-binding properties of Bacillus pasteurii (Bp) UreE. The secondary structures and global folds of BpUreE were determined for its metal-free and nickel-bound forms. The results indicated that no major structural change of BpUreE arises from the nickel binding. In addition to the previously identified nickel-binding site (Gly(97)-Cys(103)), the C-terminal tail region (Lys(141)-His(147)) was confirmed for the first time to be involved in the nickel binding. The C-terminally conserved sequence ((144)GHQH(147)) was confirmed to have an inherent nickel-binding ability. Nickel addition to 1.6 mm subunit, a concentration where BpUreE predominantly forms a tetramer upon the nickel binding, induced a biphasic spectral change consistent with binding of up to at least three nickel ions per tetrameric unit. In contrast, nickel addition to 0.1 mm subunit, a concentration at which the protein is primarily a dimer, caused a monophasic spectral change consistent with more than 1 equivalent per dimeric unit. Combined with the equilibrium dialysis results, which indicated 2.5 nickel equivalents binding per dimer at a micromolar protein concentration, the nickel-binding stoichiometry of BpUreE at a physiological concentration could be three nickel ions per dimer. Altogether, the present results provide the first detailed structural data concerning the nickel-binding properties of intact, wild-type BpUreE in solution.
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PMID:Structural characterization of the nickel-binding properties of Bacillus pasteurii urease accessory protein (Ure)E in solution. 1476 2

The ability of two soybean (Glycine max L. [Merrill]) cultivars, 'Williams 82' and 'Maple Arrow', which were reported to use different ureide degradation pathways, to degrade the ureides allantoin and allantoate was investigated. Protein fractions and total leaf homogenates from the fourth trifoliate leaves of both cultivars were examined for the ability to evolve either (14)CO(2) or [(14)C]urea from (14)C-labelled ureides in the presence of various inhibitors. (14)CO(2) evolution from [2,7-(14)C]allantoate was catalysed by 25-50% saturated ammonium sulphate fractions of both cultivars. This activity was inhibited by acetohydroxamate (AHA), which has been used to inhibit plant ureases, but not by phenylphosphorodiamidate (PPD), a more specific urease inhibitor. Thus, in both cultivars, allantoate may be metabolized by allantoate amidohydrolase. This activity was sensitive to EDTA, consistent with previous reports demonstrating that allantoate amidohydrolase requires manganese for full activity. Total leaf homogenates of both cultivars evolved both (14)CO(2) and [(14)C]urea from [2,7-(14)C] (ureido carbon labelled) allantoin, not previously reported in either 'Williams 82' or in 'Maple Arrow'. In situ leaf degradation of (14)C-labelled allantoin confirmed that both urea and CO(2)/NH(3) are direct products of ureide degradation. Growth of plants in the presence of PPD under fixing and non-fixing conditions caused urea accumulation in both cultivars, but did not have a significant impact on total seed nitrogen. Urea levels were higher in N-fixing plants of both cultivars. Contrary to previous reports, no significant biochemical difference was found in the ability of these two cultivars to degrade ureides under the conditions used.
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PMID:Soybean cultivars 'Williams 82' and 'Maple Arrow' produce both urea and ammonia during ureide degradation. 1502 Jun 40

Globally, urea is the most widely used nitrogen fertilizer and is made accessible to plants via the urease reaction. However, sequence information for the plant enzyme is scarce. A cDNA encoding urease from soybean (Glycine max) has been cloned and sequence information has been obtained for two alleles (11 and 19 kbp, respectively) of the potato (Solanum tuberosum, cv. Desiree) urease gene and the corresponding cDNAs. It was found that urease is encoded by a single copy gene in several solanaceous species, and maps to chromosome V in potato. By contrast, the presence of two urease genes was reported for soybean. Comparative analysis of 11 kbp overlapping allelic DNA allowed the quantification of single nucleotide polymorphisms and revealed the presence of a truncated Ty1-copia retrotransposon in one of the alleles. Both alleles contained a copy of a terminal-repeat retrotransposon in miniature (TRIM). 25-50% of urease pre-mRNAs from both alleles were alternatively spliced in a variety of different ways. The retrotransposons had no effect on splicing. While urease is expressed in all tissues tested, its mRNA and protein are of low abundance. The TATA-less urease promoter appears to drive low-level housekeeping transcription. An in silico analysis showed that eukaryotic urease protein sequences are very similar to sequences from prokaryotic enzymes, conserving all residues of known functional importance. It is therefore likely that all known ureases are structurally similar, employing the same catalytic mechanism.
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PMID:Analysis of two alleles of the urease gene from potato: polymorphisms, expression, and extensive alternative splicing of the corresponding mRNA. 1553 83

Short peptides resembling the Helicobacter pylori urease antigen (UreB F8 Ser-Ile-Lys-Glu-Asp-Val-Gln-Phe) with deleted aspartic acid and glutamic acid residues, anchored through a triazine linker via the N-terminal moiety to cellulose plate were prepared. The peptides were used for binding of antibodies from sera of patients with medically confirmed atherosclerosis. Recognition of the peptides was also tested with anti-Jack beans urease antibodies. The important role of a Gly-Gly spacer separating the peptides from the cellulose support was shown. Different patterns of binding of antibodies from H. pylori infected patients and anti-Jack bean urease antibodies were observed only in the case of pentapeptides. The peptide Gly-Gly-Leu-Val-Phe-Lys-Thr was recognized by most of the tested sera.
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PMID:Synthetic peptides mimicking antigenic epitope of Helicobacter pylori urease. 1649 40

Cells of 20 isolates of Yersinia (Pasteurella) pestis exhibited an unusual nutritional requirement which could be fulfilled by glycine or l-threonine. Meiotrophic mutants which required neither of these amino acids (Gly/Thr(+)) were isolated from cultures of all 20 strains at a frequency of 10(-7). Wild-type and Gly/Thr(+) cells of 14 strains failed to utilize l-amino acids or urea (0.01 m) as primary sources of nitrogen and grew slowly in the presence of low concentrations of NH(4) (+) (<== 5 mm). Cells of six strains (termed N(+)) utilized certain l-amino acids and urea (0.01 m) as primary sources of nitrogen and grew rapidly in the presence of <== 5 mm NH(4) (+). N(+) but not N(-) organisms cultivated with NH(4) (+) (0.01 m) as a primary source of nitrogen excreted a complete spectrum of naturally occurring amino acids; under this condition of growth the aspartase and particulate nicotinamide adenine dinucleotide phosphate transhydrogenase activities of N(+) and N(-) cells were repressed. N(+) meiotrophs arose at a frequency of 10(-6) in cultures of all 14 N(-) isolates, and urease-positive meiotrophs could be selected at a frequency of 10(-7) from N(+) but not N(-) cells of all 20 strains on a medium containing urea (0.01 m) as a primary source of nitrogen. These findings illustrate a reversible loss of genetic potential which has occurred during the evolution of Y. pestis as an obligate parasite and suggest that this organism is unable to efficiently remove dispensable deoxyribonucleic acid from its chromosome.
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PMID:Mutations Influencing the Assimilation of Nitrogen by Yersinia pestis. 1655 21

Recent work in our laboratory showed that the adverse effect of urea fertilizer on seed germination and seedling growth in soil is due to ammonia produced through hydrolysis of urea by soil urease (NH(2)CONH(2) + H(2)O --> 2NH(3) + CO(2)) and can be eliminated by amending the fertilizer with a small amount of a urease inhibitor such as phenylphosphorodiamidate. Because the leaf-tip necrosis often observed after foliar fertilization of plants with urea is usually attributed to ammonia formed through hydrolysis of urea by plant urease, we studied the possibility that this necrosis could be eliminated or reduced by adding phenylphosphorodiamidate to the urea fertilizer. We found that, although addition of this urease inhibitor to foliar-applied urea increased the urea content and decreased the ammonia content and urease activity of soybean [Glycine max. (L.) Merr.] leaves fertilized with urea, it increased the leaf-tip necrosis observed after fertilization. We conclude that this necrosis resulted from accumulation of toxic amounts of urea rather than from formation of toxic amounts of ammonia. This conclusion was supported by our finding that the necrotic areas of soybean leaves treated with urea or with urea and phenylphosphorodiamidate contained much higher concentrations of urea than did the nonnecrotic areas.
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PMID:Phytotoxicity of foliar-applied urea. 1659 77

Cultured soybean (Glycine max, Kanrich variety) cells grow with 25 mm urea as the sole nitrogen source but at a slower rate than with the Murashige and Skoog (MS) (Physiol. Plant. 15: 473-497, 1962) nitrogen source of 18.8 mm KNO(3) and 20.6 mm NH(4)NO(3). Growth with urea is restricted by 18.8 mm NO(3) (-), 50 mm methylammonia, 10 mm citrate or 100 mum hydroxyurea, substances which are much less restrictive or nonrestrictive in the presence of ammonia nitrogen source. The restrictive conditions of urea assimilation were examined as possible bases for selection schemes to recover urease-overproducing mutants. Since urease has higher methionine levels than the soybean seed proteins among which it is found, such selections may be a model for improving seed protein quality by plant cell culture techniques.Callus will not grow with 1 mm urea plus 18.8 mm KNO(3). Urease levels decrease 80% within two divisions after transfer from MS nitrogen source to 1 mm urea plus 18.8 mm KNO(3). Hydroxyurea is a potent inhibitor of soybean urease and this appears to be the basis for its inhibition of urea utilization by callus cells.Stationary phase suspension cultures grown with MS nitrogen source exhibit trace or zero urease levels. Soon after transfer to fresh medium (24 hours after escape from lag), urease levels increase in the presence of both MS or urea nitrogen source. However, the increase is 10 to 20 times greater in the presence of urea. NH(4)Cl (50 mm) lowers urease induction by 50% whereas 50 mm methylammonium chloride results in more drastic reductions in urea-stimulated urease levels. Citrate (10 mm) completely blocks urease synthesis in the presence of urea.Ammonia and methylammonia do not inhibit soybean urease nor do they appreciably inhibit urea uptake by suspension cultures. It appears likely that methylammonia inhibits urea utilization in cultured soybean cells primarily due to its "repressive" effect on urease synthesis.Citrate does not inhibit urease activity in vitro and exhibits only a partial inhibition (0-50% in several experiments) of urea uptake. It appears likely that the citrate elimination of urease production by cultured soybean cells is due to its chelation of trace Ni(2+) in the growth medium. Dixon et al. (J. Am. Chem. Soc. 97: 4131-4133, 1975) have reported that jack bean (Canavalia ensiformis) urease contains nickel at the active site.
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PMID:Nitrogen metabolism in soybean tissue culture: I. Assimilation of urea. 1665 77

Potassium citrate (10 mM, pH 6) inhibits the growth of cultured (Glycine max L.) cells when urea is the sole nitrogen source. Ureadependent citrate toxicity is overcome by three separate additions to the growth medium: (a) NH(4)Cl (20 mM); (b) high levels of MgCl(2) (10 mM) or CaCl(2) (5-10 mM); (c) low levels of NiSO(4) (10(-2) mM). Additions of 10(-2) mM NiSO(4) not only overcome citrate growth inhibition but the resultant growth is usually better than urea-supported growth in basal medium (neither added citrate nor added nickel). In the absence of added citrate, exceedingly low levels of NiSO(4) (10(-4) mM) strongly stimulate urea-supported growth in suspension cultures.Citrate does not inhibit growth when arginine is sole nitrogen source. However, cells using arginine have no net urease synthesis in the presence of 10 mM potassium citrate. When 10(-2) mM NiSO(4) is added to this medium, urease specific activity is 10 times that observed in basal medium lacking both citrate and added nickel.Citrate is a chelator of divalent cations. That additional Mg(2+) or Ca(2+) alleviates urea-dependent citrate toxicity indicates that citrate is acting by chelation, probably of another trace divalent cation; this is probably Ni(2+) since at 10(-2) mM it overcomes citrate toxicity and at 10(-4) mM it stimulates urea-supported growth in the absence of citrate. That ammonia overcomes citrate toxicity indicates that the trace Ni(2+) is essential specifically for the conversion of urea to ammonia. Ni(2+) stimulation of urease levels in arginine-grown cells supports this contention.In basal medium, soybean cells grow slowly with urea nitrogen source presumably because the trace amounts of Ni(2+) present (</=10(-6) mM) are growth-limiting.
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PMID:Nitrogen Metabolism in Soybean Tissue Culture: II. Urea Utilization and Urease Synthesis Require Ni. 1665 50

Itachi, a soybean (Glycine max [L.] Merr.) variety with 0.2% normal seed urease activity, was recovered from a screen of 6,000 entries in the United States Department of Agriculture soybean germplasm collection. No urease antigen in Itachi seed extracts was detected by double diffusion or by rocket immunoelectrophoresis. Native gels stained for protein or ureolytic activity revealed no detectable urease holoenzyme. An anti-urease antibody affinity column was used to remove all detectable urease activity and antigen from ;wild type' (cv. Prize) seed extracts. Affinity column effluent and nonchromatographed Itachi extracts both lack a species which comigrates with purified urease subunits in sodium dodecylsulfate polyacrylamide gels. Inability to detect urease antigen or urease protein suggests that during development of Itachi seeds there is no synthesis of urease protein or that, at most, its synthesis is 0.2% of wild type (Prize).No urease activity or only traces of urease activity were detected in cotyledons of developing or germinating Itachi seeds. In contrast, callus cultures induced from cotyledon, shoot tip, root, or root tip tissues of Itachi seedlings exhibited ureolytic activity equivalent to that of Prize cultures. Shoot tip cultures of both Prize and Itachi grew with urea as sole nitrogen source. Most or all of the ureolytic activity in crude extracts of Prize and Itachi suspension culture cells is seed-like urease in thermal stability, recognition by antibodies to the seed enzyme, hydroxyurea sensitivity, and nickel requirement for synthesis. It has been reported previously (Polacco, Havir 1979 J Biol Chem 254: 1707-1715; Polacco, Sparks, Jr, Havir 1979 Genet Eng 1: 241-259) that partially purified cell culture urease is identical to seed urease by immunological and electrophoretic criteria. These results suggest that urease is under different developmental controls in the seed and in cell culture.In both Prize and Itachi cultures, utilization of the ureide allantoin, unlike that of urea, is not dependent on nickel. This suggests that ureide catabolism does not require urease.
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PMID:A soybean seed urease-null produces urease in cell culture. 1666 76


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