Cleaves peptide bonds on the C-terminal side of prolyl residues within peptides that are up to approximately 30 amino acids long. Hydrolysis of Pro-|-Xaa >> Ala-|-Xaa in oligopeptides. Inhibited by chymostatin, Boc-Glu(NHO-Bz)-Pyrrolidide, Z-Pro-L-prolinal dimethyacetal and the peptide H-H-L-P-P-P-V-OH. Resistance to lithium due to elevation of inositol (1,4,5) trisphosphate. Belongs to the peptidase S9A family.