Narcissus pseudonarcissus lectin or agglutinin (NPL/NPA) is affinity purified composed of four subunits. It agglutinates rabbit erythrocytes but is non-reactive with human erythrocytes. NPA has an isoelectric point between pH 4.2 and pH 4.6 with a specific binding activity toward Î±-D-mannose, although studies have suggested that the purified lectin may have greater affinity for internal mannosyl residues than for nonreducing terminal units. A buffer washed column elutes the sugar Î±-methylmannoside.Human studies have found NPA to be nearly non-mitogenic, but it has been reported through an in vitro study that mitogenicity of NPA is age-related, with lymphoproliferative response of peripheral blood mononuclear cells (PBMC) in umbilical cord blood has a sevenfold increase than adult blood. NPA has also been found to be mitogenic for PBMC from lambs and not adult sheep.Alkaline phosphatase (AP) is conjugated to Narcissus pseudonarcissus Lectin (NPL/NPA) to show the binding of NPL/NPA in many applications including Western blotting and ELISA. Alkaline phosphatase is a large protein (140 kDa) that catalyzes the hydrolysis of phosphate groups from a substrate resulting in a colored or fluorescent product. The optimal enzymatic activity of this protein is between pH 8 and 10, and its reaction rate remains linear, improving sensitivity over time.