Angiotensinogen (1-14), human is a fragment of the renin substrate angiotensinogen, a precursor for all angiotensin peptides. In Vitro: Angiotensinogen (AGT) is the only precursor of all angiotensin peptides. Human AGT has 485 amino acids, including a 33 amino-acid signal peptide. The 10 N-terminal amino acids are cleaved by renin to provide angiotensin I (AngI), which is the source for an array of active angiotensin peptides^[1].