Bifunctional ligands of the bradykinin B2 and B1 receptors: An exercise in peptide hormone plasticity

•Modification of the fragile bradykinin-related peptides has a long history.•Antagonist behavior and resistance to peptidases have been pursued.•Also conjugation with a fluorophore, a drug, an epitope or a cleavable sequence.•Recent biotechnological ligands are fusion proteins that bind to kinin receptors.