Space life sciences

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

Urease reaction rates at low water activity

  • J. Skujiņš
  • A. D. McLaren


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.


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.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Belyakova, M. I., Gusarov, B. G., Krasnoshchekov, V. V., and Sinyak, Y. Y.: 1968,Kosmicheskaya Biologiya i Meditsina 2 (2), 48.Google Scholar
  2. Benesch, R. E., Lardy, H. A., and Benesch, R.: 1955,J. Biol. Chem. 216, 663.Google Scholar
  3. Blake, F. C. and Greenewalt, C. H.: 1928, inInternational Critical Tables, Vol. 3 (ed. by E. W. Washburn) McGraw-Hill, New York, N.Y., p. 302.Google Scholar
  4. Creeth, J. M. and Nichol, L. W.: 1960,Biochem. J. 77, 230.Google Scholar
  5. Deasy, C. L.: 1947,J. Am. Chem. Soc. 69, 294.Google Scholar
  6. Fischgold, H.: 1934,Biochem. J. 28, 406.Google Scholar
  7. Fishbein, W. N.: 1969,Ann. N. Y. Acad. Sci. 147, 857.Google Scholar
  8. Hanabusa, K.: 1961,Nature 189, 551.Google Scholar
  9. Hoare, J. P. and Laidler K. J.: 1950,J. Am. Chem. Soc. 72, 2487.Google Scholar
  10. Kistiakowsky, G. B., Mangelsdorf, P. C. Jr., Rosenberg, A. J., and Shaw, W. H. R.: 1952,J. Am. Chem. Soc. 74, 5015.Google Scholar
  11. Kistiakowsky, G. B. and Rosenberg, A. J.: 1952,J. Am. Chem. Soc. 74, 5020.Google Scholar
  12. Kliore, A., Fjeldbo, G., Seidel, B. L., and Rasool, S. I.: 1969,Science 166, 1393.Google Scholar
  13. McLaren, A. D. and Rowen, J. W.: 1951,J. Polymer Sci. 7, 289.Google Scholar
  14. Miller, S. L.: 1957Ann. N. Y. Acad. Sci. 69, 260.Google Scholar
  15. Oka, S.: 1930,J. Soc. Chem. Ind. Japan 33, 227B.Google Scholar
  16. Owen, T. and Mason, H. P.: 1969,Science 165, 893.Google Scholar
  17. Pittendrigh, C. S., Vishniac, W., and Pearman, J. P. T.: 1966,Biology and the Exploration of Mars, National Academy of Sciences, Washington, D.C., Publication 1296.Google Scholar
  18. Ponnamperuma, C. and Gabel, N. W.: 1968,Space Life Sci. 1, 64.Google Scholar
  19. Reithel, F. J. and Robbins, J. E.: 1967,Arch. Biochem. Biophys. 120, 158.Google Scholar
  20. Sakai, W.: 1940,J. Soc. Chem. Ind. Japan 43, 131B.Google Scholar
  21. Shnidman, L. and Sunier, A. A.: 1932,J. Phys. Chem. 36, 1232.Google Scholar
  22. Skujiņš, J. J. and McLaren A. D.: 1967,Science 158, 1569.Google Scholar
  23. Skujiņš J. J. and McLaren, A. D.: 1969,Soil Biol. Biochem. 1, 89.Google Scholar
  24. Sumner, J. B., Hand, D. B., and Holloway, R. G.: 1931,J. Biol. Chem. 91, 333.Google Scholar
  25. Watt, G. W. and Chrisp, J. D.: 1954,Anal. Chem. 26, 452.Google Scholar
  26. Weast, R. C. and Selby, S. M.: 1967,Handbook of Chemistry and Physics, 48th Edition, Chemical Rubber Publishing Co., Cleveland, Ohio, p. D-110.Google Scholar

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

Personalised recommendations