The kinetic effects resulting from changes in the medium ionic strength on reactions involving trypsin or α-chymotrypsin are different. The reaction rate increases continuously as the ionic strength increases with α-chymotrypsin. With trypsin, the rate increases at low ionic strengths but as the ionic strength further increases a gradual inhibitory effect is observed. The effects produced by different salts of various valence types (from uni-univalent to uni-trivalent or tri-univalent) are essentially the same, and they are a function of the square root of the ionic strength. The quantitative differences among the various salts may be accounted for on the basis of individual properties of the ions, such as the size of the hydrated ion, "association," etc. The effects of salts on the enzymic reactions described herein are amenable to the same electrostatic treatment applicable to non-enzymatic reactions. By applying Brönsted's basic kinetic concepts and the Debye-Hückel law of electrolyte activity, it appears that the salt effects are mainly due to changes in the dissociation of ionizable groups. This appears to be a general method for analyzing the effect of inorganic ions on enzymic reactions.
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1 July 1961
Article|
July 01 1961
Effect of Ionic Strength on the Kinetics of Trypsin and Alpha Chymotrypsin
M. Castañeda-Agulló,
M. Castañeda-Agulló
From the Laboratory of Biophysics, National School of Biological Sciences, Polytechnic Institute, México, D. F., and the Department of Food Science and Technology, University of California, Davis
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Luz M. del Castillo,
Luz M. del Castillo
From the Laboratory of Biophysics, National School of Biological Sciences, Polytechnic Institute, México, D. F., and the Department of Food Science and Technology, University of California, Davis
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J. R. Whitaker,
J. R. Whitaker
From the Laboratory of Biophysics, National School of Biological Sciences, Polytechnic Institute, México, D. F., and the Department of Food Science and Technology, University of California, Davis
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A. L. Tappel
A. L. Tappel
From the Laboratory of Biophysics, National School of Biological Sciences, Polytechnic Institute, México, D. F., and the Department of Food Science and Technology, University of California, Davis
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M. Castañeda-Agulló
From the Laboratory of Biophysics, National School of Biological Sciences, Polytechnic Institute, México, D. F., and the Department of Food Science and Technology, University of California, Davis
Luz M. del Castillo
From the Laboratory of Biophysics, National School of Biological Sciences, Polytechnic Institute, México, D. F., and the Department of Food Science and Technology, University of California, Davis
J. R. Whitaker
From the Laboratory of Biophysics, National School of Biological Sciences, Polytechnic Institute, México, D. F., and the Department of Food Science and Technology, University of California, Davis
A. L. Tappel
From the Laboratory of Biophysics, National School of Biological Sciences, Polytechnic Institute, México, D. F., and the Department of Food Science and Technology, University of California, Davis
Received:
November 04 1960
Online ISSN: 1540-7748
Print ISSN: 0022-1295
Copyright, 1961, by The Rockefeller Institute
1961
J Gen Physiol (1961) 44 (6): 1103–1120.
Article history
Received:
November 04 1960
Citation
M. Castañeda-Agulló, Luz M. del Castillo, J. R. Whitaker, A. L. Tappel; Effect of Ionic Strength on the Kinetics of Trypsin and Alpha Chymotrypsin . J Gen Physiol 1 July 1961; 44 (6): 1103–1120. doi: https://doi.org/10.1085/jgp.44.6.1103
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