nine efficient aldolase antibodies were generated using hapten 2 . this hapten combines , in a single molecule , structural components employed for reactive immunization with structural components employed for forming a transition state analog of the aldol reaction . characterization of two of these antibodies reveals that they are highly proficient and enantioselective catalysts for aldol and retro - aldol reactions and exhibit enantio - and diastereo - selectivities opposite that of antibody 38c2 .