Lys-[Des-Arg9]Bradykinin TFA is a naturally occurring kinin that serves as a potent and highly selective agonist for the bradykinin B1 receptor, demonstrating binding affinities (K i values) of 0.12 nM, 1.7 nM, and 0.23 nM for the human, mouse, and rabbit B1 receptors, respectively. This compound exhibits low inhibitory activity on B2 receptors [1] [2].