The molecular basis of the effect of temperature on enzyme activity

  • Daniel R
  • Peterson M
  • Danson M
 et al. 
  • 2

    Readers

    Mendeley users who have this article in their library.
  • N/A

    Citations

    Citations of this article.

Abstract

Experimental data show that the effect of temperature on enzymes cannot be adequately explained in terms of a two-state model based on increases in activity and denaturation. The Equilibrium Model provides a quantitative explanation of enzyme thermal behaviour under reaction conditions by introducing an inactive (but not denatured) intermediate in rapid equilibrium with the active form. The temperature midpoint (T eq ) of the rapid equilibration between the two forms is related to the growth temperature of the organism, and the enthalpy of the equilibrium (ΔH eq ) to its ability to function over various temperature ranges. In the present study, we show that the difference between the active and inactive forms is at the enzyme active site. The results reveal an apparently universal mechanism, independent of enzyme reaction or structure, based at or near the active site, by which enzymes lose activity as temperature rises, as opposed to denaturation which is global. Results show that activity losses below T eq may lead to significant errors in the determination of ΔG* cat made on the basis of the two-state ('Classical') model, and the measured k cat will then not be a true indication of an enzyme's catalytic power. Overall, the results provide a molecular rationale for observations that the active site tends to be more flexible than the enzyme as a whole, and that activity losses precede denaturation, and provide a general explanation in molecular terms for the effect of temperature on enzyme activity. © The Authors Journal compilation.

Author-supplied keywords

  • Adaptation
  • Enzyme
  • Equilibrium Model
  • Evolution
  • Kinetics
  • Temperature

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Authors

  • R.M. Daniel

  • M.E. Peterson

  • M.J. Danson

  • N.C. Price

  • S.M. Kelly

  • C.R. Monk

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free