Preferentially acts as a leucyl-aminopeptidase, although it also has activity against other substrates. 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 1 zinc ion per subunit. Optimum pH is 6. Optimum temperature is 80 degrees Celsius. Co-immunoprecipitates with the 60 kDa chaperonin. Can be phosphorylated by cell extracts. Belongs to the peptidase M1 family.