Anti-pappalysin 2 antibodies are used in the immunodetection of the protein encoded by the PAPPA2 gene. In humans, the canonical protein has a reported length of 1791 amino acid residues and a mass of 198.5 kDa. It is known to be a secreted protein. Alternative splicing is reported to yield 2 different isoforms for this protein. It is noted to be expressed abundantly in placenta, and non-pregnant mammary gland with low expression in the kidney, fetal brain and pancreas. A member of the Peptidase M43B protein family, it is known to be involved with receptor-mediated signaling pathways and proteolysis. Post-translational modifications have been described, including glycosylation. Other names for this target antigen include pregnancy-associated plasma preproprotein-A2, pregnancy-associated plasma protein E1, and placenta-specific 3.