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:6.3.4.6 (urease)
7,490 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Studies with two uropathogenic urease-producing Escherichia coli strains, 1021 and 1440, indicated that the urease genes of each are distinct. Recombinant plasmids encoding urease activity from E. coli 1021 and 1440 differed in their restriction endonuclease cleavage sites and showed minimal DNA hybridization under stringent conditions. The polypeptides encoded by the DNA fragments containing the 1021 and 1440 urease loci differed in electrophoretic mobility under reducing conditions. Regulation of urease gene expression differed in the two ureolytic E. coli. The E. coli 1021 locus is probably chromosomally encoded and has DNA homology to Klebsiella, Citrobacter, Enterobacter, and Serratia species and to about one-half of the urease-producing E. coli tested. The E. coli 1440 locus is plasmid encoded; plasmids with DNA homology to the 1440 locus probe were found in urease-producing Salmonella spp., Providencia stuartii, and two E. coli isolates. In addition, the 1440 urease probe was homologous to Proteus mirabilis DNA.
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PMID:Genetic analysis of Escherichia coli urease genes: evidence for two distinct loci. 217 68

Proteus mirabilis, a common cause of urinary tract infection, can lead to serious complications including pyelonephritis. Adherence factors, urease, and hemolysin may be virulence determinants. These factors were compared for bacteria cultured from 16 patients with acute pyelonephritis and 35 with catheter-associated bacteriuria and for 20 fecal isolates. Pyelonephritis isolates were more likely (P less than .05) to express the mannose-resistant/Proteus-like (MR/P) hemagglutinin in the absence of mannose-resistant/Klebsiella-like (MR/K) hemagglutinin than were catheter-associated or fecal isolates. Pyelonephritis isolates produced urease activity of 63 +/- 27 (mean +/- SD) mumol of NH3/min/mg of protein, not significantly different from catheter-associated or fecal isolates. Hybridization of Southern blots of P. mirabilis chromosomal DNA with two urease gene probes demonstrated that urease gene sequences were conserved in all isolates. Geometric mean of reciprocal hemolytic titers for pyelonephritis isolates was 27.9; for urinary catheter isolates, 18.0; and for fecal isolates, 55.7 (not significantly different, P greater than .1). Although in vivo expression of urease and hemolysin may not be reliable indexes of virulence, MR/P hemagglutination in the absence of MR/K hemagglutination may be necessary for development of pyelonephritis.
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PMID:Hemagglutinin, urease, and hemolysin production by Proteus mirabilis from clinical sources. 217 24

A fragment of chromosomal DNA from proteus vulgaris encoding urease was cloned and expressed in Escherichia coli. A 3 kbp region was sequenced and revealed three open reading frames with homology to jack bean (Canavalia ensiformis) urease. The smallest protein (11 kDa) was homologous to the N-terminus of the plant enzyme and the largest polypeptide (61 kDa) corresponded to the C-terminus. The large protein contained conserved regions and a cysteine residue which is known to be catalytically important in the plant enzyme. A protein of 12 kDa showed homology to residues 132 to 237 of jack bean urease.
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PMID:Cloning of the genes encoding urease from Proteus vulgaris and sequencing of the structural genes. 218 82

Nucleotide sequence analysis of a Ureaplasma urealyticum DNA fragment, homologous to cloned urease genes of other prokaryotes, revealed three consecutive open reading frames. The molecular weights of the three deduced polypeptides are 11.2 kD, 13.6 kD and 66.6 kD. These values are consistent with the size of the three subunits previously reported for purified native urease. A significant sequence homology was found between the three polypeptides of the ureaplasmal urease and the single polypeptide of jack bean (Canavalia ensiformis) urease. Codon usage indicates that UGA is a tryptophan codon in this mollicute. Use of polymerase chain reactions has disclosed the existence of genetic polymorphism among the urease genes of different serotypes of U. urealyticum.
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PMID:Ureaplasma urealyticum urease genes; use of a UGA tryptophan codon. 219 Nov 84

RNA editing, a process that results in the production of RNA molecules having a nucleotide sequence different from that of the initial DNA template, has been demonstrated in several organisms using different biochemical pathways. Very recently RNA editing was described in plant mitochondria following the discovery that the sequence of certain wheat and Oenothera cDNAs is different from the nucleotide sequence of the corresponding genes. The main conversion observed was C to U, leading to amino acid changes in the deduced protein sequence when these modifications occurred in an open reading frame. In this communication we show the first attempt to isolate and sequence a protein encoded by a plant mitochondrial gene. Subunit 9 of the wheat mitochondrial ATP synthase complex was purified to apparent homogeneity and the sequence of the first 32 amino acid residues was determined. We have observed that at position 7 leucine was obtained by protein sequencing, instead of the serine predicted from the previously determined genomic sequence. Also we found phenylalanine at position 28 instead of a leucine residue. Both amino acid conversions, UCA (serine) to UUA (leucine) and CUC (leucine) to UUC (phenylalanine), imply a C to U change. Thus our results seem to confirm, at the protein level, the RNA editing process in plant mitochondria.
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PMID:Direct protein sequencing of wheat mitochondrial ATP synthase subunit 9 confirms RNA editing in plants. 219 74

We report a rapid and reproducible method to quantify total DNA at picogram levels. Two high-affinity DNA-binding proteins are used to construct a sandwich assay and a semiconductor sensor is used for quantitation. Single-stranded DNA-binding protein (SSB) from Escherichia coli is conjugated with a linker molecule, biotin, for specific capture of the DNA complex onto a membrane. Monoclonal anti-DNA antibody is conjugated with an enzyme, urease, for signal generation. To detect DNA, a sample is denatured to form single-stranded DNA and then incubated with a reagent containing both DNA-binding protein conjugates and streptavidin. After incubation of the reagent with the DNA sample for 1 h at 37 degrees C to form a complex of streptavidin--biotin--SSB--DNA--anti-DNA--urease, the mixture is filtered through a biotin-coated nitrocellulose membrane which binds the streptavidin component of the complex. The unbound reagent is washed off the membrane, and then the captured DNA complex is detected with a light-addressable potentiometric sensor which measures the pH change catalyzed by the urease in the complex. This assay can detect 2 pg of DNA with a quantitation coefficient of variation of less than 10% in the range 10 to 200 pg.
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PMID:Picogram quantitation of total DNA using DNA-binding proteins in a silicon sensor-based system. 220 Mar 3

A 4.8-kilobase-pair region of cloned DNA encoding the genes of the Klebsiella aerogenes urease operon has been sequenced. Six closely spaced open reading frames were found: ureA (encoding a peptide of 11.1 kilodaltons [kDa]), ureB (11.7-kDa peptide), ureC (60.3-kDa peptide), ureE (17.6-kDa peptide), ureF (25.2-kDa peptide), and ureG (21.9-kDa peptide). Immediately after the ureG gene is a putative rho-dependent transcription terminator. The three subunits of the nickel-containing enzyme are encoded by ureA, ureB, and ureC based on protein structural studies and sequence homology to jack bean urease. Potential roles for ureE, ureF, and ureG were explored by deleting these accessory genes from the operon. The deletion mutant produced inactive urease, which was partially purified and found to have the same subunit stoichiometry and native size as the active enzyme but which contained no significant levels of nickel. The three accessory genes were able to activate apo-urease in vivo when they were cloned into a compatible expression vector and cotransformed into cells carrying the plasmid containing ureA, ureB, and ureC. Thus, one or more of the ureE, ureF, or ureG gene products are involved in nickel incorporation into urease.
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PMID:Sequence of the Klebsiella aerogenes urease genes and evidence for accessory proteins facilitating nickel incorporation. 221 15

CDC group M-6 is the vernacular name given to a gram-negative, oxidase-positive, aerobic, nonmotile, rod-shaped bacterium. This organism is biochemically similar to Kingella denitrificans and displays a cellular fatty acid profile consistent with CDC groups M-5 and EF-4 and with Neisseria elongata. Of the 95 M-6 strains referred to the Centers for Disease Control (CDC) for identification, 32 (64%) of the first 50 were from the throat or sputum and only 3 (6%) were from blood; only 5 (11%) of the next 45 isolates were from the upper respiratory tract and 23 (51%) were from blood, with many of these (15 or 65%) being associated with endocarditis. The major characteristics of CDC group M-6 include reduction of nitrate and nitrite with no gas formation; positive reaction for oxidase; negative reactions for catalase, urease, indole, and motility; and no acid production from carbohydrates. Guanine-plus-cytosine content determined spectrophotometrically by thermal denaturation was 55 to 58 mol % for six M-6 strains tested: 56 mol % for the N. elongata subsp. elongata type strain and for the N. elongata subsp. glycolytica type strain. By the hydroxyapatite method, DNAs from 24 M-6 strains showed an average of 78% relatedness to M-6 reference strain B1019 in reactions at 60 degrees C and 73% relatedness in reactions at 75 degrees C. M-6 strain B1019 was 79% related to the N. elongata type strain at 60 degrees C and 71% related at 75 degrees C; it was 75% related to the type strain N. elongata subsp. glycolytica at 60 degrees C and was 66% related at 75 degrees C. DNAs from CDC group EF-4, K. denitrificans, and CDC group M-5 were all less than 14% related to CDC group M-6 at 75 degrees C. The DNA relatedness data showed conclusively that all the M-6 strains belong in the species N. elongata. M-6 is different from N. elongata subsp. elongata in that M-6 reduces nitrate and sometimes weakly acidifies D-glucose, and it is different from N. elongata subsp. glycolytica in that it reduces nitrate and is negative for glucose and catalase. Because of the apparent clinical significance of M-6 compared with the clinical significance of N. elongata subsp. elongata and N. elongata subsp. glycolytica and the ease in distinguishing it biochemically, we propose M-6 as a third subspecies of N.elongata, N. elongata subsp. nitroreducens subsp. nov.
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PMID:Neisseria elongata subsp. nitroreducens subsp. nov., formerly CDC group M-6, a gram-negative bacterium associated with endocarditis. 227 87

With the increase of extremely specific polypeptide drugs arising from advances in recombinant DNA techniques, there exists a need with which to optimally deliver these genetically engineered drugs. This results from the normally short circulating half-life of these macromolecules. A well characterized model enzyme, urease, was formulated in a 20, 30, and 35% w/w poloxamer 407 gel matrix and the release profile determined in a membraneless diffusion system (Area = 11.4 cm2) in vitro at 37 degrees C over 8 hours. Polymer release into a pH = 7.0 phosphate buffer receptor phase due to matrix erosion was constant throughout 8 hours and ranged from 1.07% +/- 0.04 cm-2 hr-1 to 0.48% +/- 0.02 cm-2 hr-1 for the 20% w/w and 35% w/w poloxamer gel matrices, respectively. The predominant mechanism governing release of protein from the semisolid, poloxamer 407 gel matrix in vitro was matrix erosion with the cumulative urease released ranging from 89.5% +/- 3.5 after 7 hours (20% w/w, n = 3) to 46.6% +/- 0.3 following 8 hours of released (35% w/w, n = 3), respectively. The percent relative biological activity of the enzyme [(Act.poly/Act.cont)*100] remaining was determined following incubation in a 14% w/w concentration of poloxamer 407 for 8 hours at 4, 22, and 37 degrees C. The percent relative enzyme activity remaining following incubation in the 14% w/w poloxamer 407 solution after 8 hours was not significantly different (p greater than 0.05) between samples incubated at 4 degrees C (94.2% +/- 2.4) and 37 degrees C (89.7% +/- 1.7). Hydrodynamic properties of dilute urease and poloxamer 407 solutions were assessed using viscometry.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Sustained-release of urease from a poloxamer gel matrix. 233 5

Morganella morganii, a very common cause of catheter-associated bacteriuria, was previously classified with the genus Proteus on the basis of urease production. M. morganii constitutively synthesizes a urease distinct from that of other uropathogens. The enzyme, purified 175-fold by passage through DEAE-Sepharose, phenyl-Sepharose, Mono-Q, and Superose 6 chromatography resins, was found to have a native molecular size of 590 kilodaltons and was composed of three distinct subunits with apparent molecular sizes of 63, 15, and 6 kilodaltons, respectively. Amino-terminal analysis of the subunit polypeptides revealed a high degree of conservation of amino acid sequence between jack bean and Proteus mirabilis ureases. Km for urea equalled 0.8 mM. Antiserum prepared against purified enzyme inhibited activity by 43% at a 1:2 dilution after 1 h of incubation. All urease activity was immunoprecipitated from cytosol by a 1:16 dilution. Antiserum did not precipitate ureases of other species except for one Providencia rettgeri strain but did recognize the large subunits of ureases of Providencia and Proteus species on Western blots (immunoblots). Thirteen urease-positive cosmid clones of Morganella chromosomal DNA shared a 3.5-kilobase (kb) BamHI fragment. Urease gene sequences were localized to a 7.1-kb EcoRI-SalI fragment. Tn5 mutagenesis revealed that between 3.3 and 6.6 kb of DNA were necessary for enzyme activity. A Morganella urease DNA probe did not hybridize with gene sequences of other species tested. Morganella urease antiserum recognized identical subunit polypeptides on Western blots of cytosol from the wild-type strain and Escherichia coli bearing the recombinant clone which corresponded to those seen in denatured urease. Although the wild-type strain and recombinant clone produced equal amounts of urease protein, the clone produced less than 1% of the enzyme activity of the wild-type strain.
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PMID:Morganella morganii urease: purification, characterization, and isolation of gene sequences. 234 35


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