Topic
Urease
About: Urease is a research topic. Over the lifetime, 3464 publications have been published within this topic receiving 100435 citations. The topic is also known as: Urease & GO:0035550.
Papers published on a yearly basis
Papers
More filters
TL;DR: Combinations of reagents are described for the catalyzed indophenol reaction for the determination of ammonia, which produces a stable blue color, and the procedure is adapted to thedetermination of urea after hydrolysis with urease.
Abstract: Combinations of reagents are described for the catalyzed indophenol reaction for the determination of ammonia, which produces a stable blue color. The procedure is adapted to the determination of urea after hydrolysis with urease.
3,453 citations
TL;DR: In this paper, a rapid assay for soil urease in the absence of bacteriostatic agents has been developed, which comprises incubation of soil with an aqueous or buffered urea solution, extraction of ammonium with 1 N KCl and 0.01 NHCl and colorimetric NH4+ determination by a modified indophenol reaction.
Abstract: A rapid assay for soil urease in the absence of bacteriostatic agents has been developed. The method comprises incubation of soil with an aqueous or buffered urea solution, extraction of ammonium with 1 N KCl and 0.01 NHCl and colorimetric NH4
+ determination by a modified indophenol reaction. The method is characterized by high sensitivity and stability of the coloured complex formed. Measurements obtained by this method showed that no change in urease activity occurred when field-moist samples of soils were stored at −20°C for as long as 5 months. Air-drying of field-moist soil samples may lead to an increase in urease activity.
1,600 citations
TL;DR: The crystal structure of the K. aerogenes enzyme has been determined and provides important insight into the mechanism of catalysis, and accessory genes have been shown to be required for activation of urease apoprotein, and roles for the accessory proteins in metallocenter assembly have been proposed.
1,244 citations
TL;DR: Urease is a high-molecular-weight, multimeric, nickel-containing enzyme that plays an important role in utilization of environmental nitrogenous compounds and urea-based fertilizers.
1,238 citations
TL;DR: Kinetic studies indicate that urease activity and its affinity to urea are significantly high at the pH where calcite precipitation is favorable, suggesting a potential use of the microbial calcites precipitation process in remediation of the surface and subsurface of porous media.
Abstract: The process of microbial mineral plugging in porous media is common in nature. We examined physical and biochemical properties of CaCO3 precipitation induced by Bacillus pasteurii, an alkalophilic soil microorganism. X-ray diffraction analysis quantified the composition of the mineral deposited in sand and identified the CaCO3 crystal as calcite. Examination by scanning electron microscopy identified bacteria in the middle of calcite crystals, which acted as nucleation sites. The rate of microbiological CaCO3 precipitation correlated with cell growth and was significantly faster than that of chemical precipitation. Biochemical properties of urease (urea amidohydrolase, E.C. 3.5.1.5) from B. pasteurii that was indirectly involved in CaCO3 precipitation were examined to understand the kinetics of the microbiological process. Urease from B. pasteurii exhibited a relatively low affinity for urea at pH 7.0 with a Km of 41.6 mM and Vmax of 3.55 mM min−1 mg−1 protein and increased affinity at pH 7.7 with a Km of 26.2 mM and Vmax of 1.72 mM min−1 mg−1 protein. Results of kinetic studies indicate that urease activity and its affinity to urea are significantly high at the pH where calcite precipitation is favorable. Our findings further suggest a potential use of the microbial calcite precipitation process in remediation of the surface and subsurface of porous media.
1,198 citations