Urease was purified 500-fold to electrophoretic homogeneity from ground, dry soybeans. Sodium dodecyl sulfate-acrylamide gel electrophoresis indicates a subunit size of 93,500 daltons which is identical with that of jack bean urease. In solutions of high ionic strength, there exists a single urease species (species 1) with a size of about 480,000 daltons based on agarose column chromatography a...

sulfonic acid functionalized sba-15 (sba-pr-so3h) with pore size 6 nm as an efficient heterogeneous nanoporous solid acid catalyst exhibited good catalytic activity in the biginelli-like reaction in the synthesis of spiroheterobicyclic rings with good yield and good recyclability. spiro-pyrimidinethiones/spiro-pyrimidinones-barbituric acid derivatives were synthesized in a simple and efficient ...

Helicobacter pylori is a human pathogen that infects over 50% of the population worldwide. It is the most important etiologic agent of gastroduodenal ulcers and malignancies. Helicobacter pylori urease enzyme is considered the main factor for the organism's colonization in the gastroduodenal mucosa. Hens immunized with the purified urease produce a highly specific anti-H. pylori urease immunogl...

The proton pump inhibitors omeprazole and lansoprazole and its acid-activated derivative AG-2000, which are potent and specific inhibitors of urease of Helicobacter pylori (K. Nagata, H. Satoh, T. Iwahi, T. Shimoyama, and T. Tamura, Antimicrob. Agents Chemother. 37:769-774, 1993), inhibited the growth of H. pylori. The growth was inhibited not only in urease-positive clinical isolates but also ...

The acetohydroxamic acid (AHA), a potent inhibitor of urease, inhibits soybean urease competitively and reversibly. The I 50 and K i value for AHA were 900 M and 0.053 mM, respectively at pH 7.0, 37 °C. The variation in pH over the pH 6 9 affected K i and therefore binding of AHA in the active site. The affinity of AHA for the active site decreases with lowering of pH (below the pK a value of ...

When urea is added to Ureaplasma urealyticum, it is hydrolysed internally by a cytosolic urease. Under our measuring conditions, and at an external pH of 6.0, urea hydrolysis caused an ammonia chemical potential equivalent to almost 80 mV and, simultaneously, an increase in proton electrochemical potential (delta p) of about 24 mV with resultant de novo ATP synthesis. Inhibition of the urease w...

The aim of this work was to evaluate the effect of two different humic acid (HA) fractions, high molecular weight (HMW 100–300 kDa) and low molecular weight (LMW 10–20 kDa), extracted from peat on the activity and stability of Jack Bean urease. HMW HA significantly inhibited urease activity at pH 6.0 but did not influence the activity at pH 7.0 and 8.0. HMW HA stabilised urease activity over a ...

To study the cytotoxic effect of Helicobacter pylori on the gastric P3cosa, gastric glands harvested from guinea pigs were incubated with clinical isolates of H. pylori. H. pylori alone (H group), urea alone (U group), H. pylori plus urea (HU group), and H. pylori plus urea and the urease inhibitor acetohydroxamic acid (HUA group) were incubated with isolated gastric glands. The controls were i...

Urease and the cytotoxin VacA are two major virulence factors of the human pathogen Helicobacter pylori, which is responsible for severe gastroduodenal diseases. Diffusion of urea, the substrate of urease, into the stomach is critically required for the survival of infecting H. pylori. We now show that VacA increases the transepithelial flux of urea across model epithelia by inducing an unsatur...