Anti-Sp56 antibodies enable researchers to detect and measure the Sp56 antigen in biological samples. This target is a reported synonym of the SELENBP1 gene, which encodes selenium binding protein 1. This protein is known to function in protein transport, among other biological roles. The human version of Sp56 has a canonical amino acid length of 472 residues and a protein mass of 52.4 kilodaltons, although 4 isoforms have been identified. It is reported to be localized in the membrane, nucleus, and cytoplasm of cells and notably expressed in many tissues, such as the colon and duodenum. Other names for this target antigen include EHMTO, HEL-S-134P, and LPSB.