Effects of thermodynamic nonideality in ligand binding studies

Ford C.L., Winzor D.J., Nichol L.W. and Sculley M.J. (1983) Effects of thermodynamic nonideality in ligand binding studies. Biophysical Chemistry, 18 1: 1-9. doi:10.1016/0301-4622(83)80021-0


Author Ford C.L.
Winzor D.J.
Nichol L.W.
Sculley M.J.
Title Effects of thermodynamic nonideality in ligand binding studies
Journal name Biophysical Chemistry   Check publisher's open access policy
ISSN 0301-4622
Publication date 1983-05-01
Sub-type Article (original research)
DOI 10.1016/0301-4622(83)80021-0
Open Access Status Not yet assessed
Volume 18
Issue 1
Start page 1
End page 9
Total pages 9
Language eng
Subject 1304 Biophysics
1303 Biochemistry
1605 Organic Chemistry
Abstract Effects of thermodynamic nonideality are considered in relation to the quantitative characterization of the interaction between a small ligand. S, and a macromolecular acceptor. A, by two types of experimental procedure. The first involves determination of the concentration of ligand in dialysis equilibrium with the acceptor/ligand mixture, and the second, measurement of the concentration of unbound ligand in the reaction mixture by ultrafiltration or the rate of dialysis method. For each situation explicit expressions are formulated for the appropriate binding function with allowance for composition-dependent nonideality effects expressed in terms of molar volume, charge-charge interaction and covolume contributions. The magnitudes of these effects are explored with the aid of experimental studies on the binding of tryptophan and of methyl orange to bovine serum albumin. It is concluded for experiments conducted utilizing eiiher equilibrium dialysis or frontal gel chromatography that, provided a correction is made for any Donnan redistribution of ligand, theoretically predicted acceptor-concentration dependence is likely to be negligible and that use of the conventional binding equation written for an ideal system is appropriate to the analysis of the results. Use of ultrafiltration or the rate of dialysis method requires examination of the assumption that the activity coefficient ratio yy/y for the reaction mixture approximates unity; but again reassurance is provided that nonideality manifested as a dependence of the binding function on acceptor concentration is unlikely to be significant.
Keyword Covolume effect
Ligand binding
Thermodynamic nonideality
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import - Archived
 
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