dekoningward-novelmechanism-1997.pdf (473.87 kB)
A novel mechanism of urease regulation in Yersinia enterocolitica
journal contribution
posted on 1997-02-15, 00:00 authored by Tania De Koning-WardTania De Koning-Ward, R M Robins-BrowneYersinia enterocolitica produces the enzyme urease which hydrolyses urea, resulting in the production of carbonic acid and ammonia and a net increase in pH. In the presence of urea, urease enhances survival of Y. enterocolitica in the stomach and presumably in other acidic environments the bacteria encounter during the course of infection. In this study we show that Y. enterocolitica urease is a cytosolic enzyme which has a low Km value (0.15 +/- 0.01 mM urea), suggesting that it functions at close to maximum velocity even at the low concentrations of urea available to Y. enterocolitica in gastric fluid and other tissues. Y. enterocolitica urease was active over a wide pH range, but unlike most other bacterial ureases, displayed an optimal activity at pH 3.5-4.5, suggesting a physiological role in protecting the bacteria from acid. Higher levels of urease activity were attained at 28 degrees C than at 37 degrees C, and investigation of the regulation of urease production revealed that the enzyme was not induced by urea, or by nitrogen limitation. Instead maximal activity was attained during the stationary phase of growth which coincides with the period of maximum acid tolerance of the bacteria. This type of regulation has not been described for any other ureolytic bacteria and seems to be unique to Y. enterocolitica.
History
Journal
FEMS microbiol lettersVolume
147Issue
2Pagination
221 - 226Publisher
Oxford University PressLocation
Oxford, Eng.Publisher DOI
ISSN
0378-1097Language
engPublication classification
CN.1 Other journal articleCopyright notice
1997, ElsevierUsage metrics
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No categories selectedKeywords
Bacterial ProteinsCatalaseElectrophoresis, Polyacrylamide GelEnzyme InductionHydrogen-Ion ConcentrationImmunoblottingNADH DehydrogenaseNitrogenS PhaseTemperatureUreaUreaseYersinia enterocoliticabeta-LactamasesScience & TechnologyLife Sciences & BiomedicineMicrobiologyenzyme regulationESCHERICHIA-COLIGENETIC ORGANIZATIONMICROBIAL UREASESPURIFICATIONEXPRESSIONPH
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