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The Kirkwood-Buff theory and the effect of cosolvents on biochemical reactions

Shimizu, S. and Boon, C.L. (2004) The Kirkwood-Buff theory and the effect of cosolvents on biochemical reactions. The Journal of Chemical Physics, 121 (18). pp. 9147-9155. ISSN 0021-9606

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Cosolvents added to aqueous solutions of biomolecules profoundly affect protein stability, as well as biochemical equilibria. Some cosolvents, such as urea and guanidine hydrochloride, denature proteins, whereas others, such as osmolytes and crowders, stabilize the native structures of proteins. The way cosolvents interact with biomolecules is crucial information required to understand the cosolvent effect at a molecular level. We present a statistical mechanical framework based upon Kirkwood–Buff theory, which enables one to extract this picture from experimental data. The combination of two experimental results, namely, the cosolvent-induced equilibrium shift and the partial molar volume change upon the reaction, supplimented by the structural change, is shown to yield the number of water and cosolvent molecules bound or released during a reaction. Previously, denaturation experiments (e.g., m-value analysis) were analyzed by empirical and stoichiometric solvent-binding models, while the effects of osmolytes and crowders were analyzed by the approximate molecular crowding approach for low cosolvent concentration. Here we synthesize these previous approaches in a rigorous statistical mechanical treatment, which is applicable at any cosolvent concentration. The usefulness and accuracy of previous approaches was also evaluated.

Item Type: Article
Institution: The University of York
Academic Units: The University of York > Chemistry (York)
Depositing User: York RAE Import
Date Deposited: 16 Feb 2009 10:18
Last Modified: 16 Feb 2009 10:18
Published Version: http://dx.doi.org/10.1063/1.1806402
Status: Published
Publisher: American Institute of Physics
Identification Number: 10.1063/1.1806402
URI: http://eprints.whiterose.ac.uk/id/eprint/7618

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