Thermodynamics of hCG--monoclonal antibody interaction: an analysis of real time kinetics data obtained using radiolabeled hCG probe.
A thermodynamic analysis of the interaction of 125I-labeled human chorionic gonadotropin (IhCG) with two of its monoclonal antibodies (MAbs) was carried out. The dissociation profile of IhCG-MAb complex conforms to a two-step model. vant Hoff enthalpies were calculated with the K(A) (equilibrium constant) values obtained from dissociation at different temperatures. Free energy and entropy changes were calculated using the standard equations. DeltaH values for one of the MAbs, viz. VM7 were favorable at temperatures beyond 30 degrees C. Interestingly, the DeltaS values were also favorable at all temperatures. In the case of MAb VM4a, however, the interaction throughout the temperature range was driven by large favorable entropic contributions, indicating the importance of hydrophobic interaction in the binding of this MAb to hCG. The energetics of the interaction of these two monoclonals with hCG is discussed.
Primate Research Laboratory, Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, India.
Banerjee
B
Ashish
P
P
Tamil Selvi
Gundlupet Satyanarayana
GS
Murthy
D000911:Antibodies, Monoclonal / Q000737:chemistry*; D000937:Antigen-Antibody Reactions; D006063:Chorionic Gonadotropin / Q000737:chemistry* / Q000276:immunology; D007457:Iodine Radioisotopes; D007700:Kinetics; D013696:Temperature; D013816:Thermodynamics
D000911:Antibodies, Monoclonal; D006063:Chorionic Gonadotropin; D007457:Iodine Radioisotopes