The Effect of Temperature on the Catalytic Activity of Bovine Carbonic Anhydrase

  • John C. Kernohan
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 28)

Abstract

The two high activity forms of carbonic anhydrase which have been extensively studied, electrophoretic component C of the enzyme from human red cells and electrophoretic component B from bovine red cells, both show remarkably high catalytic activity. Under optimal conditions and at 25 C each molecule of enzyme catalyses the hydration of about 10 molecules of CO2 per second. This observation which is well established, (Kernohan, 1965; Khalifah, 1971) conflicts with a prediction by Eigen and Hammes (1963) that enzymes having acid-base catalytic mechanisms should have an upper limit of about 105 per second to their catalytic rate. This prediction comes directly from the measurement of the rate constants for the combination of protons with various bases in aqueous solution. These rate constants are found to have an upper limit of about 1011M-1sec-1 which corresponds to the collision frequency of the two reactants. For an acid with pK 6 it can be calculated that the rate constant for its dissociation of a proton cannot exceed 105 per second. For acids with higher pK values or whose conjugate bases have lower rate constants for proton addition, the rate constants for proton dissociation will be correspondingly lower. If such a group is successively protonated and then deprotonated during the catalytic action of an enzyme then the rate of the deprotonation reaction will limit the overall catalytic rate which can be achieved.

Keywords

Zinc Hydrolysis Dioxide Hydration Hydroxyl 

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References

  1. Devoe, H. and Kistiakowsky, G.B. (1961). The enzyme kinetics of carbonic anhydrase from bovine and human erythrocytes. J.Am.Chem.Soc. 83: 274.CrossRefGoogle Scholar
  2. Dixon, M. and Webb, E.G. (1964). Enzymes. 2nd Ed. London, Longmans.Google Scholar
  3. Edsall, J.T. and Wyman, J. (1958). Biophysical Chemistry, Vol. 1. New York, Academic Press.Google Scholar
  4. Eigen, M. and Be Maeyer, L. (1958). Self-dissociation and protonic charge transport in water and ice. Proc.Roy. Soc.(London) 627: 505.Google Scholar
  5. Eigen, M. and Hammes, G.G. (1963). Elementary steps in enzyme reactions. Adv.Enz. 25: 1.Google Scholar
  6. Kernohan, J.C. (1966). A method for studying the kinetics of the inhibition of carbonic anhydrase by sulphonamides. Biochim.Biophys. Acta 118: 405.PubMedGoogle Scholar
  7. Kernohan, J.C., Forrest, W.W. and Roughton, F.J.W. (1963). The activity of concentrated solutions of carbonic anhydrase. Biochim.Biophys.Acta 67: 31.PubMedCrossRefGoogle Scholar
  8. Khalifah, R.G. (1971) The carbon dioxide hydration activity of carbonic anhydrase. 1. Stop-flow kinetic studies on the native human isoenzymes B and C. J.Biol.Chem. 246: 2561.PubMedGoogle Scholar
  9. Kiese, M. (1941). Kinetic der Kohlensaureanhydrase. Biochem.Z. 307: 400.Google Scholar
  10. Liljas, A., Kannan, K.K., Bergsten, P.C., Waara, I., Fridborg, K. Strandberg, B., Carlbom, U., Jarup, L., Lovgren, S., and Petef, M. (1972). Crystal structure of human carbonic anhydrase C. Nature New Biology 235: 131.Google Scholar
  11. Lindskog, S. (1960). Purification and properties of bovine erythrocyte carbonic anhydrase. Biochim.Biophys.Acta 39: 218.PubMedCrossRefGoogle Scholar
  12. Maren, T.H. (1963). Carbonic anhydrase kinetics and inhibition at 37°: an approach to reaction rates in vivo. J.Pharmacol.Exptl.Therap. 139: 129.Google Scholar
  13. Meldrum, N.Ü. and Roughton, F.J.W. (1933) Carbonic anhydrase. Its preparation and properties. J.Physiol.(London) 80: 113.Google Scholar
  14. Roughton, F.J.W. and Booth, V.H. (1946). Effect of substrate concentration, pH and other factors upon the activity of carbonic anhydrase. Biochem.J. 40: 319.Google Scholar

Copyright information

© Plenum Press, New York 1972

Authors and Affiliations

  • John C. Kernohan
    • 1
  1. 1.Biochemistry DepartmentThe UniversityDundeeScotland

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