Sequentially removes dipeptide units (NH3-P2-P1-) from the amino termini of peptides and proteins. Is able to catalyze the removal of Asp-Arg from the amino termini of angiotensins I and II. Has slight endopeptidase activity on N-terminally blocked peptide derivatives which contain arginine residues at the P1 position. Does not hydrolyze Ala-Ala-Ala and Ala-Ala-Ala-Ala substrates or isulin beta chain. Nearly completely inhibited by 0.5 mM ZnCl(2), 0.1 mM N-tosyl-L-lysyl chloromethyl ketone (TLCK) and 0.1 mM leupeptin. Strongly inhibited by 0.5 mM CoCl(2) and 0.1 mM chymostatin. Activity is hardly affected by general serine protease inhibitors phenylmethanesulfonyl fluoride (PMSF), diisopropyl fluorophosphate (DFP) and N-tosyl-L-phenyl-alanyl chloromethyl ketone (TPCK) or by aspartyl protease inhibitor pepstatin A or by CaCl(2) and EDTA. Cysteine protease inhibitors, such as N-ethylmaleimide (NEM), iodoacetic acid and L-trans-epoxysuccinyl-leucylamido(4-guanido)butane (E-64) have no effect on activity. Optimum pH is 9.0 for the hydrolysis of Gly-Arg-pNA. No hydrolysis of Gly-Arg-pNA is detected below pH 5.5 or above pH 11.5. Stable over a broad pH range of between 7.5 and 10.0. Optimum temperature is between 35 and 40 degrees Celsius for the hydrolysis of Gly-Arg-pNA. Stable for at least 30 minutes below 20 degrees Celsius. Monomer. Belongs to the peptidase S9A family.