Peptide T, a novel bradykinin potentiator isolated from Tityus serrulatus scorpion venom.

A bradykinin-potentiating peptide was isolated and characterized from venom of the scorpion Tityus serrulatus by chromatographic techniques followed by biological assays. The complete amino acid sequence (13 residues) of peptide is presented. The peptide potentiated the contractile activity of bradykinin on the isolated guinea-pig ileum, and inhibited the hydrolysis of bradykinin by angiotensin-converting enzyme from B. jararaca plasma and the conversion of angiotensin I to angiotensin II by kininase II from guinea-pig ileum tissue. The peptide also increased the depressor effect of bradykinin on arterial blood pressure in the anaesthetized rat.