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)

Pyrocatechol was studied as an inhibitor of jack bean urease in 20 mM phosphate buffer, pH 7.0, 25 degrees C. The inhibition was monitored by an incubation procedure in the absence of substrate and reaction progress studies in the presence of substrate. It was found that pyrocatechol acted as a time- and concentration dependent irreversible inactivator of urease. The dependence of the residual activity of urease on the incubation time showed that the rate of inhibition increased with time until there was total loss of enzyme activity. The inactivation process followed a non-pseudo-first order reaction. The obtained reaction progress curves were found to be time-dependent. The plots showed that the rate of the enzyme reaction in the final stages reached zero. From protection experiments it appeared that thiol-compounds such as L-cysteine, 2-mercaptoethanol and dithiothreitol prevented urease from pyrocatechol inactivation as well as the substrate, urea, and the competitive inhibitor boric acid. These results proved that the urease active site was involved in the pyrocatechol inactivation.
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PMID:Irreversible inhibition of jack bean urease by pyrocatechol. 1469 8

We show that diffusion of single urease enzyme molecules increases in the presence of urea in a concentration-dependent manner and calculate the force responsible for this increase. Urease diffusion measured using fluorescence correlation spectroscopy increased by 16-28% over buffer controls at urea concentrations ranging from 0.001 to 1 M. This increase was significantly attenuated when urease was inhibited with pyrocatechol, demonstrating that the increase in diffusion was the result of enzyme catalysis of urea. Local molecular pH changes as measured using the pH-dependent fluorescence lifetime of SNARF-1 conjugated to urease were not sufficient to explain the increase in diffusion. Thus, a force generated by self-electrophoresis remains the most plausible explanation. This force, evaluated using Brownian dynamics simulations, was 12 pN per reaction turnover. These measurements demonstrate force generation by a single enzyme molecule and lay the foundation for a further understanding of biological force generation and the development of enzyme-driven nanomotors.
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PMID:Substrate catalysis enhances single-enzyme diffusion. 2010 65