The ANPEP gene encodes Aminopeptidase N (APN), also known as CD13 or Alanyl Aminopeptidase. The deduced amino acid sequence of APN consists of a short cytoplasmic tail, a transmembrane region, a Ser/Thr rich region, and a zinc metalloproteinase domain. Widely expressed in many cells, tissues, and species, APN cleaves the N-terminal amino acids from bioactive peptides, leading to their inactivation or degradation. It has putative involvement in several biological processes including antigen processing and presentation, cell adhesion, tumor invasion and metastasis, neurotransmitter degradation, and it also serves as a receptor for certain coronaviruses.