Aminopeptidase with broad substrate specificity. Has lower activity with substrates that have Asp or Glu in the P2' position, or Pro in the P3' position. Lacks activity with substrates that have both Pro in the P3' position and Asp or Glu in the P2' position (PubMed:25752612). Lacks carboxypeptidase activity. Lacks dipeptidyl-peptidase IV type activity (PubMed:25752612). Binds 2 Zn(2+) ions per subunit. Inhibited by bestatin. Homodimer. Ileal brush border membrane. Detected in small intestine (at protein level) (PubMed:25752612). Detected in ileum (PubMed:9388249). Detected in small intestine, spleen and testis. Isoform 2 and isoform 3 are found in the small intestine and colon (PubMed:10085079). N-glycosylated. Belongs to the peptidase M28 family. M28B subfamily. Was originally shown to have aminopeptidase IV activity (PubMed:10085079). Later characterization was unable to detect any significant aminopeptidase IV activity (PubMed:25752612).