Anti-ACE2 antibodies are used in the immunodetection of the protein angiotensin converting enzyme 2. In humans, the canonical protein has a reported length of 805 amino acid residues and a mass of 92.5 kDa. Its subcellular localization is in the cell membrane, cytoplasm, and is secreted. Up to 2 different isoforms have been reported for this protein. It is reported to be expressed in endothelial cells from small and large arteries, and in arterial smooth muscle cells. A member of the Peptidase M2 protein family, ACE2 is known to be an important counter-regulatory carboxypeptidase of the renin-angiotensin hormone system that is a critical regulator of blood volume, systemic vascular resistance, and thus cardiovascular homeostasis. Post-translational modifications have been described, including N-glycosylation, protein cleavage and phosphorylation. Synonyms for this target antigen include angiotensin I converting enzyme (peptidyl-dipeptidase A) 2, angiotensin I converting enzyme 2, angiotensin-converting enzyme homolog, and ACE-related carboxypeptidase. ACE2 gene orthologs have been reported in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.