Published Online: 15 NOV 2012
Copyright © 2001 John Wiley & Sons, Ltd. All rights reserved.
How to Cite
Emerson, J. P., Le, V. H. and Lewis, E. A. 2012. Calorimetry. eLS. .
- Published Online: 15 NOV 2012
In biology, particularly in studies relating the structure of biopolymers to their functions, two of the most important questions are: (1) how tightly does a small molecule bind to a specific interaction site? and (2) if the small molecule is a substrate and is converted to a product, how fast does the reaction take place? Because almost any chemical reaction or physical change is accompanied by a change in heat or enthalpy, an isothermal titration calorimeter is an ideal instrument to measure either how much of a reaction has taken place or the rate at which a reaction is occurring. In contrast to optical methods, calorimetric measurements can be done with reactants that are spectroscopically silent (a chromophore or fluorophore tag is not required), can be done on opaque, turbid or heterogeneous solutions (e.g. cell suspensions) and can be done over a range of biologically relevant conditions (temperature, salt, pH, etc).
Almost all chemical reactions are accompanied by a change in heat or enthalpy.
Calorimetry can determine the complete set of thermodynamic parameters that characterise binding reactions, for example K, ΔG°, ΔH°, ΔS° and ΔCp.
Binding reactions are typically pH, salt and temperature dependant.
- isothermal titration calorimetry (ITC)