Determination of thermodynamic parameters of antigen–antibody interaction from real-time kinetic studies

Tamil, Selvi P and Banerjee, Ashish and Murthy, GS (2002) Determination of thermodynamic parameters of antigen–antibody interaction from real-time kinetic studies. In: Current Science, 82 (12). pp. 1442-1448.

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Abstract

Real-time kinetic parameters of the interaction of iodinated human chorionic gonodotropin (IhCG) with one of its monoclonal antibodies are sought and are determined after an analysis of the dissociation profile of IhCG–MAb (monoclonal antibody) complexes in the presence of excess unlabelled hCG at various temperatures. The equilibrium association constant $\(K_A\)$ of the epitope–paratope reaction (the first interaction) was determined from this data. $K_A$ values obtained at different temperatures were fitted to the nonlinear form of the vant Hoff equation. Values of ln $K_{A0}$, $\Delta H_0 $ and $\Delta C_P $ were obtained from the fit. $\Delta G_0$ and $\Delta S_0$ were calculated using standard formulae. A change in heat capacity at constant pressure, $\Delta C_P$ of – 3300 cal/ degree/mol indicated that a large surface area is buried upon complex formation. This method can be an alternative to the micro-calorimetric determination of thermodynamic parameters of ligand–ligate interaction. Our results also raise new questions about the interpretations of micro-calorimetry results from large-molecular weight ligand–ligate interactions.

Item Type:	Journal Article
Publication:	Current Science
Publisher:	Indian Academy of Sciences
Additional Information:	The Copyright belongs to Indian Academy of Sciences.
Keywords:	Animals;Chordates;Humans;Mammals;Primates;Vertebrates
Department/Centre:	Division of Biological Sciences > Molecular Reproduction, Development & Genetics
Date Deposited:	13 Oct 2007
Last Modified:	19 Sep 2010 04:40
URI:	http://eprints.iisc.ac.in/id/eprint/12272

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