Anti-APP antibodies are used in the immunodetection of the protein amyloid beta precursor protein. In humans, the canonical protein has a reported length of 770 amino acid residues and a mass of 86.9 kDa. Its subcellular localization is in the cell membrane, cytoplasmic vesicles, and cytoplasm. Up to 11 different isoforms have been reported for this protein. It is reported to be expressed in the brain and in cerebrospinal fluid. A member of the APP protein family, APP is known to function as a cell surface receptor and performs physiological functions on the surface of neurons relevant to neurite growth, neuronal adhesion and axonogenesis. Post-translational modifications have been described, including O-glycosylation, N-glycosylation, acetylation, protein cleavage, sulfation and phosphorylation. APP is also used as a cellular marker for characterizing neuronal cells. Synonyms for this target antigen include ABETA, ABPP, AD1, APPI, CTFgamma, CVAP, PN-II, and AAA. APP gene orthologs have been reported in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.