Calorimetric determination of the standard transformed enthalpy of a biochemical reaction at specified pH and pMg.


Journal Article

In a biochemical reaction there is generally a change in the binding of hydrogen ions and metal ions. Therefore, calorimetric measurements of enthalpies of reaction have to be adjusted for the enthalpies of reaction of the hydrogen ions and metal ions produced or consumed with the buffer. It can be shown that this yields the standard transformed enthalpy of reaction that determines the change in the apparent equilibrium constant K' (written in terms of sums of concentrations of species of a reactant) with temperature at the chosen pH and concentration of free metal ion. The derivations are based on the assumption that the changes in pH and free metal ion concentrations in the calorimetric experiment are small. This assumption is experimentally realized if a solution is well buffered for hydrogen and metal ions. The derived equations are discussed in terms of the implications they have for the performance and interpretation of calorimetric measurements.

Full Text

Duke Authors

Cited Authors

  • Alberty, RA; Goldberg, RN

Published Date

  • October 1993

Published In

Volume / Issue

  • 47 / 3

Start / End Page

  • 213 - 223

PubMed ID

  • 8241417

Pubmed Central ID

  • 8241417

International Standard Serial Number (ISSN)

  • 0301-4622

Digital Object Identifier (DOI)

  • 10.1016/0301-4622(93)80046-l


  • eng

Conference Location

  • Netherlands