Aminopeptidase which catalyzes the hydrolysis of amino acid residues from the N-terminus of peptide or protein substrates. Binds 1 zinc ion per subunit. Additional isoforms may exist. Expressed in testis, heart, brain, lung, liver, skeletal muscle, kidney and ovary. Expressed in vascular tissues. Belongs to the peptidase M1 family. A paper describing the expression patterns of this protein has been retracted due to concerns of image manipulation. Intron retention. This sequence is incomplete at the 5'-end and differs from that shown at positions 658-661.