Anti-SN antibodies are protein reagents that detect specific antigens. The SN antigen is another term for the human protein secretogranin II, encoded by the SCG2 gene. The protein is reported to be a neuroendocrine protein of the granin family that regulates the biogenesis of secretory granules. Canonically, it has an amino acid length of 617 residues and a mass of 70.9 kilodaltons. It is a secreted protein and it is expressed in many tissues, such as the adrenal gland and colon. The SN protein is a member of the Chromogranin/secretogranin protein family.