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)

Semipermeable nylon-polyethylenimine artificial cells containing leucine dehydrogenase (EC 1.4.1.9), alcohol dehydrogenase (EC 1.1.1.1), urease (EC 3.5.1.5), and dextran-NAD+ were prepared. Artificial cells could convert ammonia or urea into L-leucine, L-valine, and L-isoleucine. For batch conversion in 20.0 mM of ammonium acetate substrate solutions, in 2 h 0.2 ml of artificial cells could produce 4.48 mumol of L-leucine, 9.98 mumol of L-valine, or 5.96 mumol of L-isoleucine. The corresponding conversion ratios were 22.4, 49.9, and 29.8%. In 20.0 mM of urea substrate solutions, 13.71 mumol of L-leucine, 16.12 mumol of L-valine, or 13.44 mumol of L-isoleucine was produced and the conversion ratios were 68.6, 80.6, and 67.2%. The substrate specificity of leucine dehydrogenase for the reductive amination was determined. Of the three branched-chain amino acids produced, the production rates of L-valine were the highest. The apparent Km values were as follows: 0.32 mM for alpha-ketoisocaproate, 1.63 mM for alpha-ketoisovalerate, and 0.73 mM for Dl-alpha-keto-beta-methyl-n-valerate. The leucine dehydrogenase multienzyme system had a good storage stability. It retained 72.0% of the original activity with artificial cells were stored at 4 degrees C for 6 weeks. The optimum conversion pH and temperature were 8.5-9.0 and 35-40 degrees C. The effects of urea and ammonium salts on conversion rate were also studied. The relative activities in ammonium salts solutions were 45.1-75.9% of those in urea solutions.
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PMID:Conversion of ammonia or urea into essential amino acids, L-leucine, L-valine, and L-isoleucine, using artificial cells containing an immobilized multienzyme system and dextran-NAD+. 2. Yeast alcohol dehydrogenase for coenzyme recycling. 169 39

A multienzyme system consisting of leucine dehydrogenase (EC 1.4.1.9), L-lactic dehydrogenase (EC 1.1.1.27), urease (EC 3.5.1.5), and dextran-NAD+ was microencapsulated within artificial cells. This system could convert ammonia and urea into essential amino acids, L-leucine, L-valine, and L-isoleucine. L-lactate acted as a cosubstrate for the regeneration of dextran-NADH. Greater concentrations of L-lactate favored the higher conversion ratios. The effects of ammonium salts and urea on reaction rate were also studied. The relative reaction rates in ammonium salts solutions were 44.6-78.8% of those in urea solutions. More than 90% of the original activity was retained when artificial cells were kept at 4 degrees C for 6 wk.
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PMID:Conversion of ammonia or urea into essential amino acids, L-leucine, L-valine, and L-isoleucine using artificial cells containing an immobilized multienzyme system and dextran-NAD. L-lactic dehydrogenase for coenzyme recycling. 170 78

Artificial cells containing glucose dehydrogenase (EC 1.1.1.47), leucine dehydrogenase (EC 1.4.1.9), urease (EC 3.5.1.5), and dextran-NAD+ were prepared. Ammonia or urea could be converted into L-leucine, L-valine, and L-isoleucine with artificial cells. Low-specific-activity glucose dehydrogenase could effectively regenerate dextran-NADH, which was recycled at a rate of 0.4 to 0.5 cycle per minute under reaction conditions. The effects of ammonium salts and urea on the conversion rate for the leucine dehydrogenase multienzyme system were also studied. The relative activities in ammonium salts solutions were 40 to 70% of those in urea solutions.
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PMID:Conversion of ammonia or urea into L-leucine, L-valine, and L-isoleucine using artificial cells containing an immobilized multienzyme system and dextran-NAD+. Glucose dehydrogenase for co-factor recycling. 245 27

Artificial cells containing leucine dehydrogenase (EC 1.4.1.9), alcohol dehydrogenase (EC 1.1.1.1; or glucose dehydrogenase, EC 1.1.1.47; or lactic dehydrogenase, EC 1.1.1.27; or malic dehydrogenase, EC 1.1.1.37), urease (EC 3.5.1.5) and dextran-NAD+ were prepared. Ammonia or urea could be converted into L-leucine, L-valine and L-isoleucine using artificial cells with four different multienzyme systems.
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PMID:Conversion of urea or ammonia into essential amino acids (L-leucine, L-valine, and L-isoleucine) using multienzyme systems and NADH-dextran immobilised in artificial cells. 344 45

Thirty-one urease-positive thermophilic Campylobacter (UPTC) isolates, including three reference strains (NCTC12892, NCTC12895 and NCTC12896), and three Campylobacter lari isolates, which were isolated from several countries and sources, were compared genotypically by using multilocus enzyme electrophoresis (MLEE). We examined allelic variation around seven enzyme loci, including the adenylate kinase, alkaline phosphatase, catalase, fumarase, malic enzyme, malate dehydrogenase, and L-phenylalanyl-L-leucine peptidase loci. MLEE typing revealed the presence of 23 different electrophoretic types (ETs) among the 31 UPTC isolates, and 14 isolates shared six electrophoretic profiles. Three different ETs were identified for the three C. lari isolates examined, and no ETs were shared by UPTC and C. lari isolates. Quantitative analyses were subsequently performed by using allelic variation data, and the results demonstrated that the mean genetic diversity was 0.655. In conclusion, MLEE demonstrated that the UPTC isolates examined are genetically hypervariable and form a cluster separate from the C. lari cluster.
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PMID:Characterization of urease-positive thermophilic Campylobacter subspecies by multilocus enzyme electrophoresis typing. 1278 30