We　have　isolated　a　novel　bradykinin　B2-receptor　antagonist　peptide,　kinestatin,　from　toad　(Bombina　maxima)　defensive　skin　secretion.　Mass　spectroscopy　established　a　molecular　mass　of　931.56　Da　and　a　provisional　structure:　pGlu-Leu/Ile-Pro-Gly-Leu/Ile-Gly-Pro-Leu/Ile-Arg.amide.　The　unmodified　sequence,　-QIPGLGPLRG-,　was　located　at　the　C-terminus　of　a　116-amino-acid　residue　open-reading　frame　following　interrogation　of　a　sequenced　B.　maxima　skin　cDNA　library　database.　This　confirmed　the　presence　of　appropriate　primary　structural　attributes　for　the　observed　post-translational　modifications　present　on　the　mature　peptide　and　established　residue　2　as　Ile　and　residues　5/8　as　Leu.　Kinestatin　represents　a　prototype　novel　peptide　from　amphibian　skin.　©　2003　Elsevier　B.V.　All　rights　reserved.