A secreted aminopeptidase. Acts on free N-terminal amino groups with a very strong preference for Leu in the first position. Release of an N-terminal amino acid, Xaa-|-Yaa-, in which Xaa is preferably Leu, but may be other amino acids including Pro although not Arg or Lys, and Yaa may be Pro. Amino acid amides and methyl esters are also readily hydrolyzed, but rates on arylamides are exceedingly low. Binds 2 Zn(2+) ions per subunit. Belongs to the peptidase M28 family. M28A subfamily.