Bradykinin
Bradykinin — A nonapeptide that causes blood vessel dilation, studied for its role in inflammation, blood pressure regulation, and pain signaling.
What Is Bradykinin?
Bradykinin is a nonapeptide (Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg) with a molecular weight of 1060.22 Da. It is generated from high-molecular-weight kininogen by the enzyme kallikrein. Bradykinin is one of the most potent endogenous vasodilators and pain mediators, and its study has been fundamental to understanding inflammation and vascular biology.
Mechanism of Action
Bradykinin signals through two receptors: B1 (induced during inflammation) and B2 (constitutively expressed). B2 receptor activation triggers endothelial nitric oxide (NO) and prostacyclin release, causing vasodilation, increased vascular permeability, and pain sensitization through C-fiber activation.
Research Applications
- Pain research: Bradykinin is a standard algogenic agent for pain models and analgesic drug testing
- Vascular biology: Reference vasodilator for endothelial function studies
- ACE connection: ACE degrades bradykinin; ACE inhibitor side effects (cough, angioedema) result from bradykinin accumulation
- Inflammation: B1/B2 receptor antagonists studied as anti-inflammatory agents
Handling
Extremely short half-life (< 30 seconds in plasma) due to rapid cleavage by kininase II (ACE) and carboxypeptidase N. Add protease inhibitors immediately when collecting biological samples for bradykinin measurement.
Frequently Asked Questions
What is Bradykinin?
A nonapeptide that causes blood vessel dilation, studied for its role in inflammation, blood pressure regulation, and pain signaling.
Why is Bradykinin important in peptide research?
Bradykinin is a fundamental concept in compound as it relates to peptide science. It directly influences experimental design, compound characterization, and the reliability of research outcomes across biochemistry and molecular biology disciplines.