Further studies on the structure-activity relationships of bradykinin-potentiating peptides.

Several pentapeptides were synthesized and tested for bradykinin-potentiating activity. From these and previous data it appeared that an (L)-aromatic amino acid residue (preferably Trp) in position 3 is essential for high activity. Position 3 represents a stereospecific pillar function, whereas the other positions and the lipophilicity/hydrophilicity balance are important for additional activity. So far, BPP5a seems to have the optimal structure for a bradykinin-potentiating pentapeptide.