Angiotensin
A family of peptide hormones (angiotensin I, II, and III) central to blood pressure regulation. Angiotensin II is a potent vasoconstrictor produced from angiotensin I by angiotensin-converting enzyme (ACE). The angiotensin system exemplifies how peptide signalling cascades regulate cardiovascular function.
Technical Context
The angiotensin family includes: angiotensinogen (precursor, 452 aa), angiotensin I (Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-His-Leu, 10 aa — inactive), angiotensin II (Asp-Arg-Val-Tyr-Ile-His-Pro-Phe, 8 aa — the primary active peptide), angiotensin III (angiotensin II minus N-terminal Asp — stimulates aldosterone), and angiotensin(1-7) (produced by ACE2 — vasodilatory, anti-inflammatory, counterbalancing angiotensin II). Angiotensin II is one of the most potent vasoconstrictors in the body. ACE2 gained prominence during COVID-19 as the SARS-CoV-2 viral entry receptor. The complex angiotensin processing system illustrates how peptide pro-hormones can generate multiple active peptides with distinct or opposing biological effects.