HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: fj.06-7265comv1 fj.06-7265comv2 fj.06-7265comv3 21/8/1934    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lee, C. K. Articles by Peterson, M. E. Search for Related Content PubMed PubMed Citation Articles by Lee, C. K. Articles by Peterson, M. E.

Eurythermalism and the temperature dependence of enzyme activity

Charles K. Lee^*, Roy M. Daniel^*,1, Charis Shepherd, David Saul, S. Craig Cary^*,, Michael J. Danson, Robert Eisenthal^|| and Michelle E. Peterson^*

^* Department of Biological Sciences, University of Waikato, Hamilton, New Zealand;

School of Biological Sciences, University of Auckland, Auckland, New Zealand;

College of Marine and Earth Studies, University of Delaware, Lewis, Delaware, USA;

Centre for Extremophile Research, Department of Biology and Biochemistry, and

^|| Department of Biology and Biochemistry, University of Bath, Bath, UK

¹Correspondence: Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand. E-mail: r.daniel{at}waikato.ac.nz

The "Equilibrium Model" has provided new tools for describing and investigating enzyme thermal adaptation. It has been shown that the effect of temperature on enzyme activity is not only governed by G_cat and G_inact but also by two new intrinsic parameters, H_eq and T_eq, which describe the enthalpy and midpoint, respectively, of a reversible equilibrium between active and inactive (but not denatured) forms of enzyme. Twenty-one enzymes from organisms with a wide range of growth temperatures were characterized using the Equilibrium Model. Statistical analysis indicates that T_eq is a better predictor of growth temperature than enzyme stability (G_inact). As expected from the Equilibrium Model, H_eq correlates with catalytic temperature tolerance of enzymes and thus can be declared the first intrinsic and quantitative measure of enzyme eurythermalism. Other findings shed light on the evolution of psychrophilic and thermophilic enzymes. The findings suggest that the description of the Equilibrium Model of the effect of temperature on enzyme activity applies to all enzymes regardless of their temperature origins and that its associated parameters, H_eq and T_eq, are intrinsic and necessary parameters for characterizing the thermal properties of enzymes and their temperature adaptation and evolution.—Lee, C. K., Daniel, R. M., Shepherd, C., Saul, D., Cary, S. C., Danson, M. J., Eisenthal, R., Peterson, M. E. Eurythermalism and the temperature dependence of enzyme activity

Key Words: enzyme temperature optimum • Equilibrium Model • growth temperature • protein stability • temperature adaptation

This article has been cited by other articles:

				C. K. Lee, S. C. Cary, A. E. Murray, and R. M. Daniel Enzymic Approach to Eurythermalism of Alvinella pompejana and Its Episymbionts Appl. Envir. Microbiol., February 1, 2008; 74(3): 774 - 782. [Abstract] [Full Text] [PDF]