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.
Cy3 can be used to visualize the binding pattern of Styphnolobium japonicum Lectin (SJA) in cellular imaging and flow cytometry. Cy3 is more photostable than many other fluorophores and can be seen with TRITC filter sets. It is commonly combined with green-fluorescent dyes for dual-labeling.