Medicago AB Products Are Available Worldwide. For Research Use Only. Narcissus pseudonarcissus lectin (NPL) is isolated from daffodils. It exists as a dimeric protein (molecular weight 26 kDa) composed of two subunits of 13 kDa each. NPL dissociates into its monomers below pH 5.0 and above pH 9.0. NPL is mitogenic for human lymphocytes. Specificity for blood group: non-reactive with human erythrocytes. Narcissus pseudonarcissus lectin is supplied as a white lyophilized powder in 10 mM CH3COONH4. For laboratory use only.