Styphnolobium japonicum agglutinin (SJA) is affinity purified from Japanese pagoda tree seeds. It consists of two subunits. The subunits can be separated into two subfractions, a D-galactose/N-acetyl-D-galactosamine specific lectin (B-SJA-I) and a D-mannose/D-glucose specific lectin (B-SJA-II). SJA has an isoelectric point between pH 4.9 and pH 5.6 and a carbohydrate specificity towards βGalNAc. This lectin elutes with the sugar GalNAc.
SJA agglutinates all blood group types but has greater affinity for A erythrocytes than of B types, than of O (-SA) types. Binding experiments of the lectin with frozen sections of human kidneys shows specific binding to the endothelia in specimens from blood groups B or AB, thus indicating a D-galactose/N-acetyl-D-galactosamine receptor specificity. SJA lacks mitogenic and immune-suppressive activity.
Horseradish peroxidase (HRP) is a 40 kDa protein that catalyzes the oxidation of substrates by hydrogen peroxide, resulting in a colored or fluorescent product or release of light as a byproduct of the reaction. It is most commonly used for blotting, immunoassays and immunohistochemistry methods. Styphnolobium japonicum Lectin (SJA) is conjugated to HRP at an appropriate ratio to provide optimal staining characteristics.