A nine-residue kinin that dilates vessels, raises permeability and signals pain during inflammation.
Also known as: BK · kallidin-related kinin
Part of the Foundational & therapeutic peptides cluster
Overview
Bradykinin is a nine-amino-acid signaling peptide of the kinin group, released from kininogen by kallikrein. Acting through B2 and B1 receptors, it drives vasodilation, increased vascular permeability, pain signaling and inflammation, and is central to the kallikrein-kinin system. This page is educational and not medical advice.
Source & context
Biological / chemical source: Cleaved from kininogen by kallikrein enzymes
Primary research or clinical context: Vascular, inflammation and pain physiology research
Generation and receptors
Bradykinin (RPPGFSPFR) is cleaved from high-molecular-weight kininogen by plasma kallikrein. It acts mainly at the constitutive B2 receptor and, during injury, at the inducible B1 receptor, and is rapidly degraded by kininases including angiotensin-converting enzyme (ACE).
Why it matters
Because ACE also inactivates bradykinin, its accumulation explains the cough and angioedema seen with ACE-inhibitor drugs. The peptide is a key research model for vascular permeability, nociception and hereditary angioedema, where kallikrein-kinin signaling is dysregulated.
Sequence
One-letter sequence commonly cited for Bradykinin (educational; isoforms and modifications may differ):
RPPGFSPFR
Residues plotted ~100° apart around an α-helix — clustering of one color reveals an amphipathic face.
FAQ about Bradykinin
What is Bradykinin?+
Bradykinin is a nine-amino-acid signaling peptide of the kinin group, released from kininogen by kallikrein. Acting through B2 and B1 receptors, it drives vasodilation, increased vascular permeability, pain signaling and inflammation, and is central to the kallikrein-kinin system. This page is educational and not medical advice.
Is Bradykinin an approved medicine?+
Bradykinin is discussed here as a research / educational topic. Vascular, inflammation and pain physiology research. This is not medical advice.
What is the typical length of Bradykinin?+
Bradykinin is commonly described as approximately 9 amino acids (Signaling peptide (kinin)).