The important human pathogen Helicobacter pylori requires the abundant expression and activity of its urease enzyme for colonization of the gastric mucosa. The transcription, expression, and activity of H. pylori urease were previously demonstrated to be induced by nickel supplementation of growth media. Here it is demonstrated that the HP1338 protein, an ortholog of the Escherichia coli nickel...

UNLABELLED Urease in Cryptococcus neoformans plays an important role in fungal dissemination to the brain and causing meningoencephalitis. Although urea is not required for synthesis of apourease encoded by URE1, the available nitrogen source affected the expression of URE1 as well as the level of the enzyme activity. Activation of the apoenzyme requires three accessory proteins, Ure4, Ure6, an...

Helicobacter pylori survives and grows at low pHs via acid acclimation mechanisms that enable periplasmic pH homeostasis. Important components include a cytoplasmic urease; a pH-gated urea channel, UreI; and periplasmic α-carbonic anhydrase. To allow the rapid adjustment of periplasmic pH, acid acclimation components are recruited to the inner membrane in acid. The ArsRS two-component system, i...

Urease is a metalloenzyme essential for the survival of Helicobacter pylori in acidic gastric environment. Maturation of urease involves carbamylation of Lys219 and insertion of two nickel ions at its active site. This process requires GTP hydrolysis and the formation of a preactivation complex consisting of apo-urease and urease accessory proteins UreF, UreH, and UreG. UreF and UreH form a com...

With black soil (Pachic Udic Argiboroll) of Northeastern China as the test object, an incubation test was conducted to investigate the effects of urease inhibitors, hydroquinone (HQ), phenyl phosphorodiamidate (PPD) and N-(n-Butyl) thiophosphoric triamide (NBPT), on the kinetic characteristics of soil urease under normal moisture and waterlogged conditions, aimed to study the changes of catalyt...

Baicalin (BA) is the principal component of Radix Scutellariae responsible for its pharmacological activity. In this study, kinetics and mechanism of inhibition by BA against jack-bean urease were investigated for its therapeutic potential. It was revealed that the IC₅₀ of BA against jack-bean urease was 2.74 ± 0.51 mM, which was proved to be a competitive and concentration-dependent inhibition...

Urease catalyzes the hydrolysis of urea to ammonia and carbon dioxide. The ammonia (nitrogen (N) product of urease activity) is incorporated into organic compounds. Thus, urease is involved in N remobilization, as well as in primary N assimilation. Two urease isoforms have been described for soybean: the embryo-specific, encoded by the Eu1 gene, and the ubiquitous urease, encoded by Eu4. A thir...

Yersinia enterocolitica serotype O:3 and O:8 urease-negative mutants unable to express the 19-kDa beta subunit of urease were constructed and tested for virulence and arthritogenicity. Our results indicate that urease is needed for full virulence in oral infections and that it is not an arthritogenic factor in the rat model.

UNLABELLED A novel mechanism aimed at controlling urease expression in Helicobacter pylori in the presence of ample nickel is described. Higher urease activities were observed in an hp0868 mutant (than in the wild type) in cells supplemented with nickel, suggesting that the HP0868 protein (herein named Mua for modulator of urease activity) represses urease activity when nickel concentrations ar...

The Helicobacter pylori ureE gene product was previously shown to be required for urease expression, but its characteristics and role have not been determined. The UreE protein has now been overexpressed in Escherichia coli, purified, and characterized, and three altered versions were expressed to address a nickel-sequestering role of UreE. Purified UreE formed a dimer in solution and was capab...