Medicago AB Products Are Available Worldwide. For Research Use Only. Pisum sativum agglutin (PSA) is isolated from peas by affinity chromatography. It has 4 subunits and a molecular weight of 49 kDa. PSA has a carbohydrate binding specificity for α-D-mannose and α-D-glucose. The lectin agglutinates human erythrocytes without regard to blood type. PSA lectin is a mitogen similar to Concanavalin A. Pisum sativum lectin is supplied without preservatives as a white to cream-coloured lyophilized powder. For laboratory use only.