Anti-PST antibodies are protein reagents that detect specific antigens. The PST antigen is another term for the human protein ST8 alpha-N-acetyl-neuraminide alpha-2,8-sialyltransferase 4, encoded by the ST8SIA4 gene. The protein is known to catalyze the polycondensation of alpha-2,8-linked sialic acid required for the synthesis of polysialic acid (PSA), which is present on the embryonic neural cell adhesion molecule (N-CAM), necessary for plasticity of neural cells. Canonically, it has an amino acid length of 359 residues and a mass of 41.3 kilodaltons. Its subcellular localization is in the Golgi and it is reported to be highly expressed in fetal brain, lung and kidney and in adult heart, spleen and thymus. The PST protein is a member of the Glycosyltransferase 29 protein family.