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)

The objectives were to determine the responses of turkeys to soybean meals (SBM) differing in urease and trypsin inhibitor activity, to estimate the AME of diets containing these SBM, and to determine the responses to supplemental L-Met and L-Lys. Four experiments were conducted with poults 1 to 3 wk of age and one with turkeys 6 to 8 wk of age. In Experiment 1, the trypsin inhibitor activities (TI) were 1.8, 4.2, 5.4, 7.0, and 8.8 mg trypsin inhibited/g SBM (method of Hamerstrand et al., 1981). The corresponding urease indices were .02, .14, .51, .90, and 1.5 pH units. The SBM were 46% of the diet. Significant pancreatic hypertrophy occurred with dietary concentrations of TI of 3.2 mg/g and above. At 4.0 mg TI/g of diet, the feed:gain ratio was increased, but body weight gain and AME of the diet were reduced. In Experiments 2, 3, and 4, poults responded similarly to Met additions to diets containing 46% SBM with TI of 1.8 or 4 mg/g SBM, or to Met or Met plus Lys additions to diets containing 40.7 or 49.6% SBM with TI of 2 or 11 mg/g SBM. In Experiment 5, the SBM contained TI at 4.3, 6.1, 8.9, or 12.5 mg/g. The corresponding urease indices were .05, .27, 1.43, and 1.72 pH units. The SBM were 49.6% of the diet. Using 6 to 8 wk old turkeys, the AME of the four diets were determined to be 2.76, 2.71, 2.58, and 2.57 Mcal/kg. The AME of diets containing 4.4 and 6.2 mg TI/g of diet were reduced (P < .05). In conclusion, through 3 wk of age, turkeys can tolerate soybean TI concentrations of 2.5 mg TI/g of diet. Turkeys 6 to 8 wk of age can tolerate 3 mg of soybean TI/g of diet.
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PMID:Tolerance of turkeys to diets high in trypsin inhibitor activity from undertoasted soybean meals. 747 89

Several inbred strains of mice in closed breeding colonies were found to have spiral-shaped bacteria associated with active, chronic hepatitis. A new species of Helicobacter, H. hepaticus, was isolated from the infected livers of some strains of mice. Other strains of mice were colonised with H. hepaticus in the caecum and colon, but not the liver. Filtersterilised supernatant fluid from five strains of H. hepaticus was tested in a mouse liver cell line (ATCC no. CCL 9.1) for cytotoxic activity. All strains produced a toxic factor causing morphological changes in the cells at dilutions up to 1 in 1000. Toxicity was observed after exposure to the supernatant fluid for 48-72 h. Other Helicobacter spp. that also produced the cytopathic effect (CPE) in the liver cell line were H. felis, H. acinonyx, H. pylori and one strain of H. mustelae. "Helicobacter rappini" and H. muridarum did not cause CPE in the liver cells. The soluble factor was stable at 4 degrees C for up to 3 months. It was also stable at 56 degrees C for 30 min, but was inactivated by boiling for 15 min. It was inactivated by incubation with trypsin. A partially purified preparation of the cytotoxin had a mol. wt of c. 100,000 and did not have urease activity. The cytotoxin produced by H. hepaticus did not cause vacuole formation in HeLa cells.
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PMID:In-vitro hepatotoxic factor in Helicobacter hepaticus, H. pylori and other Helicobacter species. 773 25

Helicobacter pylori adhere to Kato III and Hela S3 cells in monolayer cultures. To explore whether cell surface glycoconjugates on these two cell lines mediate binding of H. pylori, various carbohydrates, glycoproteins, and glycolipids were tested to inhibit H.pylori cell adhesion. The adhesion was measured (i) with a urease-based assay and (ii) by cells stained with fluorescein. Sodium periodate and sialidase treatment (but not alpha- or beta-galactosidase, heparitinase,lysozyme, or trypsin) inhibited H. pylori binding to both cell lines. Sulfatides and sulfated glycoconjugates (50 microg/ml) but not heparin or a number of simple carbohydrates inhibited binding (1 mg/ml). The two H.pylori strains studied (CCUG 17874 and strain 25) showed high binding of soluble 125I-labeled heparin and other sulfated carbohydrate compounds.
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PMID:Sulfatides inhibit binding of Helicobacter pylori to the gastric cancer Kato III cell line. 909 25

The effects of different heat treatments were studied on chemical composition, protein degradability, amino acid composition, trypsin inhibition and urease activity. Three lactating Holstein cows fitted with rumen cannulae were used. Fullfat soybean was prepared employing different forms of heat treatment: dry-extrusion at 150 degrees C for 25 s (treatment I); wet-extrusion at 95 degrees C for 30 min (treatment II); toasted soybean at 105 degrees C for 30 min (treatment III) extracted soybean meal (treatment IV); and untreated soybean (treatment V). The incubation times were 0, 2, 4, 8, 16, 24 and 48 h. Samples of raw and heat-treated soybean before incubation and the undegraded fraction after 4 and 16 h of incubation were analyzed for amino acids. The results showed that heat treatments did not modify chemical composition, but significantly reduced the content of trypsin inhibition and urease activity, as well as decreased protein degradability. The dry extrusion technique was comparatively the most effective. Amino acid content was not significantly influenced by different techniques, but the quantity of amino acids escaping degradation in the rumen increased.
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PMID:Protein degradability, amino acid composition, trypsin inhibitor and urease activity of raw and heat-treated fullfat soybean. 934 98

Membrane enzyme reactors constitute an attempt at integrating catalytic conversion, product separation and/or concentration and catalyst recovery into a single operation. Whereas conventional membrane reactors confine an enzyme, in a free form, to one side of a membrane by size exclusion, electrostatic repulsion, or physical or chemical immobilization onto an intermediate support (gel, liposome), the membrane reactor here described is shown to operate under an entirely new principle: enzyme confinement into an isoelectric trap located in a multicompartment electrolyzer operating in an electric field. Two isoelectric membranes, having pI values encompassing both the enzyme pI and the pH of its optimum of activity, act by continuously titrating the enzyme trapped inside, thus preventing it from escaping the reaction chamber. Charged products generated by the enzyme catalysis are continuously electrophoretically transported away from the reaction chamber and collected into other chambers stacked either towards the cathodic or anodic sides. In a urease reactor, ammonia is continuously harvested towards the cathode, thus allowing >95% substrate consumption with maintenance of enzyme integrity over much longer time periods than in a batch reactor. In a trypsin reactor, casein is digested and biologically active peptides are continuously harvested in a pure form into appropriate isoelectric traps. In a third example, pure D-phenylglycine is produced from a racemate mixture, via an acylation reaction onto a cosubstrate (the ester methyl-4-hydroxyphenyl acetate), brought about by the enzyme penicillin G acylase.
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PMID:An isoelectrically trapped enzyme reactor operating in an electric field. 966 67

Ten Basidiobolus ranarum (= Basidiobolus haptosporus) strains, isolated from faeces of 102 different lower vertebrates (ectotherms) exhibited in Antwerp Zoo, or from their environment were studied for their temperature requirements, haemolysis and other enzyme activities in vitro. All isolates grew well at 25 and 37 degrees C. Three strains that produced undulated zygospore walls were haemolytic and positive for hyaluronidase. All the isolates produced urease, N-acetyl-beta-glucosaminidase, trypsin, lipase, lecithinase, gelatinase, collagenase and elastase, but failed to produce amylase, keratinase and beta-glucosidase. Three isolates failed to produce phosphatase. Only one strain failed to produce DNase. Aesculin was not hydrolysed. Chitinase activity was inconclusive. The results of this study illustrate the importance of exotic animals kept in temperate regions as carriers of potentially pathogenic organisms. In addition to the morphological characteristics, the identification can be based on enzymatic profiles. Enzymatic activity detection may help to explain the pathogenic mechanism of the fungus.
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PMID:Isolation of Basidiobolus ranarum from ectotherms in Antwerp zoo with special reference to characterization of the isolated strains. 1042 99

Two techniques for determining enzyme kinetic constants using isothermal titration microcalorimetry are presented. The methods are based on the proportionality between the rate of a reaction and the thermal power (heat/time) generated. (i) An enzyme can be titrated with increasing amounts of substrate, while pseudo-first-order conditions are maintained. (ii) Following a single injection, the change in thermal power as substrate is depleted can be continuously monitored. Both methods allow highly precise kinetic characterization in a single experiment and can be used to measure enzyme inhibition. Applicability is demonstrated using a representative enzyme from each EC classification, including (i) oxidation-reduction activity of DHFR (EC 1.5.1.3); (ii) transferase activity of creatine phosphokinase (EC 2.7.3.2) and hexokinase (EC 2.7.1.1); (iii) hydrolytic activity of Helicobacter pylori urease (EC 3.5.1.5), trypsin (EC 3.4.21.4), and the HIV-1 protease (EC 3.4.21.16); (iv) lyase activity of heparinase (EC 4.1.1.7); and (v) ligase activity of pyruvate carboxylate (EC 6.4.1.1). This nondestructive method is completely general, enabling precise analysis of reactions in spectroscopically opaque solutions, using physiological substrates. Such a universal assay may have wide applicability in functional genomics.
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PMID:Enzyme kinetics determined using calorimetry: a general assay for enzyme activity? 1155 13

Two characteristic monoclonal antibodies (HpU-2 and -18) out of 26 monoclonal antibodies (HpU-1 approximately 26) produced against Helicobacter pylori (H. pylori) urease showed a strong inhibitory effect against the enzymatic activity of the urease. Epitope mapping about some monoclonal antibodies of the HpU-series inhibiting enzymatic activity was performed by using a surface plasmon resonance apparatus and by digesting H. pylori urease with trypsin, followed by mass spectroscopy. The sequences of the epitopes recognized by HpU-2 and -18 were SVELIDIGGNRRIFGFNALVDR (22 mer) and IFGFNALVDR (10 mer), respectively. The former sequence is present as a part of a loop structure at a position close to the C-terminal of the alpha-subunit of H. pylori urease, although it has been suggested that the active site of the urease resides in the beta-subunit. The above peptide (22 mer) was chemically synthesized in a linear and cyclic form, and its conjugate with BSA was immunized in rabbits. The resultant serum induced by the linear form could specifically bind to H. pylori infecting human gastric mucosa. These results suggest that the above sequence (22 mer) must be an important epitope, although it locates in the alpha-subunit but not in the beta-subunit.
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PMID:Epitope mapping and features of the epitope for monoclonal antibodies inhibiting enzymatic activity of Helicobacter pylori urease. 1511 96

The proteolytic activities of alpha-chymotrypsin, trypsin, pepsin, bromelain, and an extract from germinating pumpkin seeds (Cucurbita moschata) were determined by their ability to effect the release of 1-anilino-8-naphthalenesulfonate bound to internal hydrophobic sites in intact protein substrates. Casein, glyceraldehyde-3-P dehydrogenase, urease, catalase, pumpkin seed globulin, and bovine serum albumin enhanced the fluorescence of 1-anilino-8-naphthalenesulfonate sufficiently to be used as proteolytic substrates. Chymotrypsin, trypsin, pepsin, and bromelain exhibited activity against all or almost all of the protein substrates. The activity of 1 mug of alpha-chymotrypsin or trypsin and 100 ng of pepsin could be easily detected by this method of assay within 4 to 5 minutes depending upon the substrate. The enzyme extracted from 3-day germinated pumpkin seeds exhibited strong activity only against pumpkin seed globulin, weak activity against the globulins of squash and cucumber and casein, and no activity against the other protein substrates. Activity against pumpkin globulin was maximal at pH 7.4. When assayed by an increase in ninhydrin-positive products, the enzyme extract from pumpkin seeds also showed strong activity against pumpkin globulin and weak activity against casein. The 1-anilino-8-naphthalenesulfonate-fluorescence method was at least 20 times more sensitive than the ninhydrin method and was 10 to 20 times more rapid.
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PMID:Globulin-specific Proteolytic Activity in Germinating Pumpkin Seeds as Detected by a Fluorescence Assay Method. 1665 2

Lactobacillus fermentum strain L23 produced a small bacteriocin, designated bacteriocin L23, with an estimated molecular mass of < 7000 Da. Isolation, purification, and partial characterization of bacteriocin L23 are described. It displayed a wide inhibitory spectrum including both Gram-negative and Gram-positive pathogenic strains and two species of Candida. The antibacterial activity of cell-free culture supernatant fluid was not affected by catalase or urease but was abolished by the proteolytic enzymes trypsin and protease VI. Bacteriocin L23 was heat stable (60 min at 100 degrees C) and showed inhibitory activity over a wide pH range (4.0 to 7.0). The proteinaceous compound was isolated from cell-free culture supernatant fluid and purified. Crude bacteriocin sample was prepared by a process of ammonium sulfate precipitation, gel filtration, thin-layer chromatography, bioautography, and reversed-phase HPLC.
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PMID:Purification and partial characterization of novel bacteriocin L23 produced by Lactobacillus fermentum L23. 1817 15


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