Abstract: Methods for synthesizing three-dimensional stabilized peptides which mimic the three-dimensional configuration of the active site of a natural, biologically active protein are carried out by (1) noting the three-dimensional configuration of the active site of a known biologically active protein (2) noting the amino acid sequence and the hydrogen bonds existing between amino acids which hydrogen bonds are capable of maintaining the three-dimensional configuration of the active site and (3) producing a synthetic three-dimensional peptide to mimic the structure of the active site. The synthetic peptide is synthesized so as to have the same or a similar amino acid sequence to the amino acid sequence of the active site of the biologically active polypeptide but with the stabilizing hydrogen bonds being replaced by a bridging divalent radical selected from the group of --(N)--C(CH.sub.3).dbd.N(H.sup.+)--CH.sub.2 --(N)--; --(N)--C(CH.sub.3).dbd.N(H.sup.+)--CH.sub.2 --CH.sub.2 --(N)--; and --(N)--N.dbd.CH--CH.sub.