Aminopeptidase with broad substrate specificity to several peptides. It has more affinity for oligopeptides than for dipeptides. It plays an essential role in the metabolism, it may be involved in nitrogen supply or protein turnover (By similarity). Release of an N-terminal amino acid, Xaa-|-Yaa- from a peptide, amide or arylamide. Xaa is preferably Ala, but may be most amino acids including Pro (slow action). When a terminal hydrophobic residue is followed by a prolyl residue, the two may be released as an intact Xaa-Pro dipeptide. Binds 1 zinc ion per subunit. Monomer. It may be secreted through an unknown mechanism. Belongs to the peptidase M1 family.