– Lysosomal Pro-X Carboxypeptidase (PRCP) belongs to the peptidase S28 family. PRCP is detected in many tissues, with highest levels observed in placenta, lung, and liver. It is also present in the heart, brain, pancreas, and kidney. PRCP exists as a homodimer. PRCP cleaves C-terminal amino acids linked to proline in peptides such as angiotensin II, III and des-Arg9-bradykinin. This cleavage occurs at acidic pH, but enzymatic activity is retained with some substrates at neutral pH. PRCP has been shown to be an activator of the cell matrix-associated prekallikrein.