Has a broad aminopeptidase activity on non-blocked peptides by progressively cleaving amino acids off the peptide substrate. Aminopeptidase activity stops at the residue before the first proline in the peptide. Cannot cleave when proline is the first N-terminal residue. Binds 2 divalent metal cations per subunit. Can use cobalt, and to a lesser extent, nickel, manganese or copper. Belongs to the peptidase M42 family.