Bradykinin potentiator C, secreted by the viper venom gland, inhibits the activity of the angiotensin-converting enzyme (ACE) and enhances the action of bradykinin by inhibiting the peptidases that inactivate it.Viper: pGlu-Gly-Leu-Pro-Pro-Gly-Pro-Pro-Ile-Pro-Pro-OH or pEGLPPGPPIPP-OH