Maclura pomifera agglutinin or lectin (MPA/MPL) is tetrameric plant protein purified by fractionation. MPA has a molecular weight of about 44,000 and consists of four subunits. It has an isoelectric point between pH 4.8 and pH 5.3, and blood group specificity towards A, B, and O (-SA). This lectin has a high affinity for tumor-associated T-antigen disaccharide (GalÎ²1,3GalNAcÎ±) and many O-linked glycopeptide structures. The structure of GalÎ²1,3GalNAcÎ± occurs on the surface of tumor cells as a mucin-associated antigenic marker, termed as T-antigen. It is also the central element in O-linked glycopeptide structures on other mammalian glycoproteins.Biotin is a small molecule involved in a wide range of metabolic processes. This ligand forms a complex with Avidin and Streptavidin, resulting in the strongest non-covalent protein-ligand interaction known. Biotinylated Maclura pomifera Lectin (MPL/MPA) has an appropriate amount of biotin bound to provide optimum detection characteristics when using an Avidin-HRP or Streptavidin-HRP conjugate. Biotinylated lectins allow for more sensitive detection in ELISA and Western-blotting applications.