Anti-PG-S1 antibodies enable researchers to detect and measure the PG-S1 antigen in biological samples. This target is a reported synonym of the BGN gene, which encodes biglycan. This protein is known to function in bone development, among other biological roles. The human version of PG-S1 has a canonical amino acid length of 368 residues and a protein mass of 41.7 kilodaltons. It is reported to be localized in the extracellular matrix and is secreted of cells and notably expressed in the placenta, kidney, heart muscle, epididymis, and adrenal gland. PG-S1 is a member of the Small leucine-rich proteoglycan (SLRP) protein family.