RELATION BETWEEN THE ACTIVITY OF CATALYTIC ANTIBODIES AND THE PROPERTIES OF SUBSTRATES

The free energy of binding between catalytic antibodies and substrates is correlated with the properties of the substrates, both in the tran sition state (TS) and the ground state (GS). The free energy of bindin g was calculated from the kinetic parameters and four properties of th e substrates; the solvent accessible surface area (SAS), enthalpy of h ydration (Delta H), polarizability (alpha), and dipole moment (mu) wer e calculated using AM1. As a whole, TS shows a higher correlation than does GS, which is compatible with the fundamental concept of a cataly tic antibody. Among these four properties, SAS gives the highest corre lation coefficient (0.7616) while mu has a small correlation. Antibody -TS complexes seem to be stabilized by van der Waals force rather than a hydrophobic interaction.