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)

A heterobifunctional reagent, N-succinimidyl 3-(2-pyridyldithio)propionate, was synthesized. Its N-hydroxysuccinimide ester group reacts with amino groups and the 2-pyridyl disulphide structure reacts with aliphatic thiols. A new thiolation procedure for proteins is based on this reagent. The procedure involves two steps. First, 2-pyridyl disulphide structures are introduced into the protein by the reaction of some of its amino groups with the N-hydroxysuccinimide ester sie of the reagent. The protein-bound 2-pyridyl disulphide structures are then reduced with dithiothreitol. This reaction can be carried out without concomitant reduction of native disulphide bonds. The technique has been used for the introduction of thiol groups de novo into ribonuclease, gamma-globulin, alpha-amylase and horseradish peroxidase. N-Succinimidyl 3-(2-pyridyldithio)propionate can also be used for the preparation of protein-protein conjugates. This application is based on the fact that protein-2-pyridyl disulphide derivatives (formed from the reaction of non-thiol proteins with the reagent) react with thiol-containing proteins (with native thiols or thiolated by, for example, the method described above) via thiol-disulphide exchange to form disulphide-linked protein-protein conjugates. This conjugation technique has been used for the preparation of an alpha-amylase-urease, a ribonuclease-albumin and a peroxidase-rabbit anti-(human transferrin) antibody conjugate. The disulphide bridges between the protein molecules can easily be split by reduction or by thiol-disulphide exchange. Thus conjugation is reversible. This has been demonstrated by scission of the ribonuclease-albumin and the alpha-amylase-urease conjugate into their components with dithiothreitol. N-Succinimidyl 3-(2-pyridyldithio)propionate has been prepared in crystalline form, in which state (if protected against humidity) it is stable on storage at room temperature (23 degrees C).
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PMID:Protein thiolation and reversible protein-protein conjugation. N-Succinimidyl 3-(2-pyridyldithio)propionate, a new heterobifunctional reagent. 70 70

The effects of serum, albumin and gammaglobulins on urease-induced crystallization have been studied in synthetic and in human urine. Serum and the studied proteins increased urease enzymatic activity in synthetic urine. In human urine only serum had this effect. In synthetic urine, the proteins and serum markedly decreased the precipitation attached to glass surfaces, while the intraluminal precipitation was increased. In human urine, similar but weaker effects on the precipitation were found for serum and albumin. These findings suggest that the proteins studied, in the concentrations in which they are present in human urine, have profound effects on urease-induced crystallization and may be physiological crystallization inhibitors.
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PMID:Effects of serum, albumin and immunoglobulins on urease-induced crystallization in urine. 210 Apr 17

To Study how the composition of urine influences urease-induced crystallization, human urine samples were incubated with urease and the subsequent precipitation measured. Beside the pH increase, the urinary content of magnesium and calcium had profound effects on the precipitation of magnesium ammonium phosphate and calcium phosphate, respectively. Urine phosphate, ammonium and osmolarity had no direct effects on the precipitation. Among the urine components with potential inhibitory properties, only albumin was found to be correlated with such an effect. This inhibitory activity was especially influential in urines with high calcium and magnesium levels. These findings suggest that the composition of urine could also influence the formation of stones consisting of magnesium ammonium phosphate and calcium phosphate.
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PMID:How variations in the composition of urine influence urease-induced crystallization. 210 Apr 18

Struvite and hydroxyapatite were precipitated from artificial urine onto the surfaces of catheter materials by the controlled addition of urease. They were precipitated both together and separately (by omitting components of the artificial urine), and with and without the inclusion of albumin (which was intended to mimic the proteinaceous debris found in infected urine). Precipitates were identified by X-ray powder diffraction and the artificially encrusted surfaces examined by scanning electron microscopy. In the presence of protein, hydroxyapatite was precipitated as a poorly crystalline form which aggregated to form a crust. Struvite crystals could be easily identified under the scanning electron microscope by their relatively large size and characteristic appearance. Fifteen encrusted catheters from patients were also examined by scanning electron microscopy, and a further six using X-ray microanalysis. Their appearance was very similar to that of the materials encrusted in vitro. Encrustation involves the formation of hydroxyapatite and the growth of struvite crystals, intimately associated with bacteria.
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PMID:Morphology of mineral deposits on encrusted urinary catheters investigated by scanning electron microscopy. 255 97

The stability of native and immobilized urease isolated from Staphylococcus saprophyticus was studied at 4 degrees and 25 degrees C. The activity yield was 20% and 1.4% on the enzyme immobilization in albumin gel and latex membrane, respectively. Inactivation of native microbial urease proceeded 10 times slower in the solution containing 1 mM EDTA and 30 mM sodium sulfite. This solution contributed to a great extent to stabilization of immobilized urease both during storage in the phosphate buffer solution and in case of lyophilization.
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PMID:[Stabilization of native and immobilized urease]. 361 80

The calculolytic effect of a diet designed to reduce the urine concentration of urea, P, and Mg was evaluated in female Beagles with induced urease-positive urinary tract infections and struvite urolithiasis and in female Beagles with induced sterile struvite urolithiasis. The reduced-protein calculolytic diet induced urolith dissolution in 5 of 6 infected dogs with struvite urolithiasis in 2 to 5 months (means = 14.4 weeks). At the end of 6 months, uroliths in comparable control dogs fed a maintenance diet were 5 times larger and 14 times heavier than at the beginning of the study. The calculolytic diet induced urolith dissolution in 6 of 6 noninfected dogs with struvite uroliths in 2 to 4 weeks (means = 3.3 weeks). Four uroliths in noninfected dogs fed the maintenance diet dissolved over a period of 2 to 5 months (means = 14 weeks). Urolith dissolution in dogs fed the calculolytic diet was associated with diet-induced diuresis, reduction in urine pH, reduction in urine concentration of urea ammonia, P, and Mg, and increase in urine titratable acidity. Consumption of the calculolytic diet was also associated with significant (P = less than 0.01) reduction in the serum concentration of urea and albumin and a significant (P = less than 0.01) increase in serum hepatic alkaline phosphatase activity. Concomitant occurrence of hydropic degeneration of hepatocytes indicated that these biochemical and morphologic changes were associated with dietary protein restriction.
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PMID:Evaluation of a calculolytic diet in female dogs with induced struvite urolithiasis. 647 63

The characteristics of an unclassified Mycobacterium sp. isolated from three patients with Crohn's disease are presented. The organism is extremely fastidious and mycobactin dependent and may require up to 18 months of incubation for primary isolation. Colony morphology is rough. Characteristics are unlike those of any presently defined species. The isolates produced postive niacin, catalase, and 2-week arylsulfatase reactions and were susceptible to neotetrazolium chloride (1:40,000), streptomycin (2 micrograms/ml), and rifampin (0.25 micrograms/ml). Chromogenicity, nitrate reduction, quantitative catalase, Tween hydrolysis, urease, tellurite reduction, pyrazinamidase, and 3-day arylsulfatase tests were negative, and the isolates were resistant to thiophene-2-carboxylic acid hydrazide (10 micrograms/ml) and isoniazid (10 micrograms/ml). Optimum growth in broth was determined to be in 7H9 medium with Dubos oleic albumin complex, Tween 80, and mycobactin J at 37 degrees C without CO2 or agitation and in low medium depth. This Mycobacterium sp. may be a subspecies or biovariant of Mycobacterium paratuberculosis, or it may represent a new species of Mycobacterium. It is suggested that this Mycobacterium sp. may play an etiological role in some cases of Crohn's disease.
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PMID:Characteristics of an unclassified Mycobacterium species isolated from patients with Crohn's disease. 651 78

Beagle serum proteins were separated by polyacrylamide gel electrophoresis (PAGE) and the electrophoretograms were examined by one- and two-dimensional analyses with a laser densitometer. In order from the anodic side of the PAGE pattern, pre-albumin, hexokinase, tyrosinase, alkaline phosphatase, urease, and aldehyde dehydrogenase were assumed to be present based on Rf and Mw. Serum albumin, lactate dehydrogenase, and catalase appeared to be present based on a comparison of their electrophoretic mobility with that of protein standards of known Mw. Verification of beagle serum protein fractions by immunofixation electrophoresis and western blotting electrophoresis, with rabbit anti-human serum, indicated alpha 1-antitrypsin, albumin, haptoglobin, ceruloplasmin, C3c complement, IgG, and IgA. Serum protein fraction values (%) obtained by one- and two-dimensional analyses were similar.
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PMID:Analysis of a polyacrylamide gel electrophoretogram of beagle serum protein by laser densitometer. 765 Sep 2

The abilities of different types of organosilanes, in particular of polymers with: 1) completely or 2) partially hydrophobical surfaces; 3) regular changes of part of silicium ions by metal ions; 4) preliminary aminosilanization were studied for sorption of ammonia ions, urea, cholesterol, creatinine, albumin, IgG, haemoglobin and myoglobin. Polymethylsiloxane was used as haemosorbent for directed sorption of myoglobin and haemoglobin from solution and blood. It didn't hemolysate red cells. The high efficiency of those organosilanes for sorption of haemoproteins it was shown. Organosilanes were very good as membrane for immobilization of urease and IgG-specific antibodies to create enzyme sensor and immunosensor based on the ionsensitive field effect transistors. The advantages and possibilities of organosilane usage as haemosorbents in the field of medicine of catastrophes as well as for sensor technology are discussed.
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PMID:[Study of sorption properties of organosilanes to be used as the basis for hemosorbents and diagnostic enzyme and immunosensors]. 984 81

The biocompatibility of modified and urease-immobilized poly(ethyleneglycol dimethacrylate/2-hydroxyethylmetacrylate) [poly(EGDMA/HEMA)] microbeads was tested through blood compatibility tests. Twelve percent HEMA incorporated nonporous particles of 105-125 microm were used in the research. Hydroxyl groups on microbeads were chemically modified by following a three-step procedure that is composed of activation, spacer-arm incorporation (hexamethylene diamine) and, finally, glutaraldehyde bounding. Enzyme urease was immobilized on microbead surfaces, and adsorption of blood proteins in serum and plasma, blood coagulation time, and leukocyte and platelet adhesion were tested. Incubation of 1.5 cc of biological fluid with 100 mg of urease-immobilized poly(EGDMA/HEMA) microbeads at room temperature shows that protein adsorption on surfaces occurs, but protein content after treatment was in the range of healthy people. Adsorbed albumin and total globulin amounts per gram of microbeads is much greater than fibrinogen. Immobilization of urease reduced the protein adsorption and blood coagulation times compared with those of modified microbeads. Prothrombin time (PT) was not altered much, whereas poly(EGDMA/HEMA) microbeads induced a significant increase of activated partial thromboplastin time (APTT). The platelet and leukocyte adhesion slightly increased with the modification of poly(EGDMA/HEMA) and decreased with the introduction of urease. When blood samples were treated with urease-immobilized microbeads, BUN values of patients were lowered to almost acceptable amounts.
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PMID:Biocompatibility investigation and urea removal from blood by urease-immobilized HEMA incorporated poly(ethyleneglycol dimethacrylate) microbeads. 1247 42


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