Abstract: Antigens capable of eliciting antibodies which can catalyze chemical reactions, in particular, the cleavage or formation of a peptide linkage, comprising a hapten or a hapten and a suitable carrier molecule are disclosed. Haptens include, among others, silicon and boron containing compounds. Antibodies which are catalytically active for chemical reactions, in particular, the cleavage or formation of a selected peptide linkage or an ester bond, and which are elicited by such antigens are disclosed as well as methods for producing the antibodies and methods for catalyzing the cleavage or formation of a peptide linkage or in ester bond in a molecule.