N-Acetyl-Ser-Asp-Lys-Pro (Ac-SDKP) acetate is a specific substrate for the N-terminal active site of angiotensin-converting enzyme (ACE). N-Acetyl-Ser-Asp-Lys-Pro acetate is a natural inhibitor of pluripotent hematopoietic stem cell proliferation. Anti-inflammatory and antifibrotic properties.