Anti-PEG antibodies are protein reagents that detect specific antigens. The PEG antigen is another term for the human protein progestagen associated endometrial protein, encoded by the PAEP gene. The protein is a reported glycoprotein that regulates critical steps during fertilization and also has immunomonomodulatory effects. Canonically, it has an amino acid length of 180 residues and a mass of 20.6 kilodaltons. It is a secreted protein and it is expressed in the endometrium and placenta. The PEG protein is a member of the Lipocalin protein family. Other alias names for PEG include GD, GdA, and GdF. Western Blot and Immunohistochemistry are common applications for PEG antibodies.