Molecular Weight: 1258.66 Salt Form: TFA Purity: >96% Sequence (3-letter): Asp-Arg-Val-Tyr-Val-His-Pro-Phe-Asn-Leu-OH Sequence (1-letter): DRVYVHPFNL-OH Storage: -20 ?C or below Angiotensin I, also known as proangiotensin is formed from angiotensigen by the action of renin. It has no direct biological function but is a precursor to angiotensin II through cleavage of the two terminal amino acids by angiotensin converting enzyme (ACE).