Cardiovascular · Angiotensinogen-derived decapeptide; angiotensin-converting enzyme substrate
Angiotensin I
Also known as Ang I; Ang-(1–10)
A renin-generated decapeptide used to investigate ACE activity and enzymatic processing within the renin–angiotensin system.
- Length
- 10 amino acids
- Half-life
- Not well characterised
- Mechanism
- Angiotensin-converting enzyme (ACE) removes the C-terminal His–Leu dipeptide to generate angiotensin II. Angiotensin I has little direct activity at AT1 or AT2 receptors; many assay responses depend on enzymatic conversion to downstream peptides.
- Studied in
- Purified-enzyme assays, vascular preparations and animal renin–angiotensin models use angiotensin I to investigate peptide processing and ACE-dependent signalling.
About Angiotensin I
Angiotensin I is the linear decapeptide Asp–Arg–Val–Tyr–Ile–His–Pro–Phe–His–Leu, released when renin cleaves angiotensinogen. It occupies an upstream position in the renin–angiotensin system rather than acting as its principal receptor agonist. Historical biochemical work distinguished the renin-generated precursor from the shorter, more active angiotensin II, establishing a two-enzyme processing pathway. The peptide has free amino and carboxyl termini and contains no disulphide bonds.
Conversion by ACE produces the octapeptide angiotensin II, which activates AT1 and AT2 receptors. Other processing pathways include ACE2-mediated formation of angiotensin-(1–9) and neprilysin-dependent generation of shorter fragments, including angiotensin-(1–7). Consequently, an apparent response to angiotensin I in a tissue preparation can reflect several locally generated products. Research commonly combines enzyme inhibitors, receptor antagonists and chromatographic peptide measurements to distinguish precursor processing from the actions of individual downstream ligands.
Laboratory notes
- For research use only. Confirm sequence, terminal chemistry and peptide content against the batch certificate before preparing assay standards.
- Use low-binding vessels and small aliquots; validate recovery and stability in the chosen buffer rather than assuming stability from nominal concentration.
- In biological matrices, quench proteolysis promptly and quantify conversion products; receptor responses alone cannot establish which angiotensin species is present.
Storage and reconstitution basics: storage guide.
Questions about Angiotensin I
Does angiotensin I directly activate AT1 receptors?
Its direct activity is weak relative to angiotensin II. In enzyme-containing preparations, AT1-dependent signals often arise after conversion to angiotensin II.
What does ACE remove from angiotensin I?
ACE cleaves the C-terminal His–Leu dipeptide, converting the ten-residue precursor into eight-residue angiotensin II.
Why can ACE inhibition leave other peptide products detectable?
Angiotensin I can also be processed by other peptidases. ACE inhibition does not block every pathway, so product-resolved analytical measurements are needed.
Is Angiotensin I for human use?
No. It is supplied strictly for in-vitro laboratory research and is not for human or animal consumption.
Related research peptides
All products are sold for laboratory research use only. Not for human consumption, not a medicine, not for diagnosing, treating or preventing any condition.