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Interpretation of the temperature dependence of equilibrium and rate constants
Author(s) -
Winzor Donald J.,
Jackson Craig M.
Publication year - 2006
Publication title -
journal of molecular recognition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.401
H-Index - 79
eISSN - 1099-1352
pISSN - 0952-3499
DOI - 10.1002/jmr.799
Subject(s) - thermodynamics , enthalpy , chemistry , arrhenius equation , interpretation (philosophy) , equilibrium constant , reaction rate constant , entropy (arrow of time) , statistical physics , standard enthalpy change of formation , transition state theory , activation energy , kinetics , physics , quantum mechanics , computer science , programming language
The objective of this review is to draw attention to potential pitfalls in attempts to glean mechanistic information from the magnitudes of standard enthalpies and entropies derived from the temperature dependence of equilibrium and rate constants for protein interactions. Problems arise because the minimalist model that suffices to describe the energy differences between initial and final states usually comprises a set of linked equilibria, each of which is characterized by its own energetics. For example, because the overall standard enthalpy is a composite of those individual values, a positive magnitude for Δ H o can still arise despite all reactions within the subset being characterized by negative enthalpy changes: designation of the reaction as being entropy driven is thus equivocal. An experimenter must always bear in mind the fact that any mechanistic interpretation of the magnitudes of thermodynamic parameters refers to the reaction model rather than the experimental system For the same reason there is little point in subjecting the temperature dependence of rate constants for protein interactions to transition‐state analysis. If comparisons with reported values of standard enthalpy and entropy of activation are needed, they are readily calculated from the empirical Arrhenius parameters. Copyright © 2006 John Wiley & Sons, Ltd.