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Space life sciences

, Volume 3, Issue 1, pp 3–11 | Cite as

Urease reaction rates at low water activity

  • J. Skujiņš
  • A. D. McLaren
Article
  • 52 Downloads

Abstract

Hydrolysis of urea by urease takes place in ‘dry’ urea-urease mixture exposed to discrete water vapor pressures from 100% to 20% relative humidity and at 2°C to 70°C. A discontinuity in enzymatic activities is observed at the transition of urea from a solid to a deliquescent solution. Urease is inactivated more readily at higher relative humidities in saturated urea solution than at lower relative humidities where water for urea hydrolysis is adsorbed on enzyme-protein only. Hydrolysis of urea by urease proceeds at a measurable rate in concentrated solutions of urea and of urea hydrolysis products, ammonium carbonate and bicarbonate, in the absence of ionic strength or pH stabilizing agents.

Keywords

Hydrolysis Urea Relative Humidity Water Vapor Bicarbonate 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© D. Reidel Publishing Company 1971

Authors and Affiliations

  • J. Skujiņš
    • 1
  • A. D. McLaren
    • 1
  1. 1.Department of Soils and Plant NutritionUniversity of CaliforniaBerkeleyUSA

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