COMPARATIVE THERMODYNAMIC ANALYSES OF THE FV, FAB(ASTERISK) AND FAB FRAGMENTS OF ANTIDANSYL MOUSE MONOCLONAL-ANTIBODY

In order to investigate the role of the constant domains on the antige n-binding property of the variable domains, we have carried out a comp arative thermodynamic study of the anti-dansyl Fv, Fab and Fab fragme nts that possess the identical amino acid sequence of the variable dom ains. The thermodynamic analyses have shown that binding constants, en thalpy changes and entropy changes are similar for the three antigen-b inding fragments, whereas the thermal stability of Fab is much higher than that of Fv and Fab. We have concluded that (i) the variable doma ins of the three antigen-binding fragments possess identical intrinsic capability for antigen binding and (ii) the two constant domains serv e to improve the stability of the variable domains.