Sambucus nigra Lectin (SNA/EBL I) is an isolectin isolated from elderberry bark and purified by affinity chromatography. SNA I belongs to the group of type 2 ribosome-inactivating proteins and is composed of an A-chain with enzymatic activity and a B-chain with carbohydrate-binding activity. It has specificity for α2,6-linked sialic acid residues, and elutes with the sugar lactose. SNA I can induce apoptosis through the caspase-dependent pathway at low concentrations. This effect depends on the carbohydrate binding of the B-chain and is independent from the catalytic activity of the A-chain.
Sambucus nigra Lectin (SNA/EBL I) is conjugated to ferritin, that has a molecular weight of 474,000 g/mol (all 24 subunits combined). Ferritin-conjugated lectins can be used to visualize localization of specific saccharide moieties and examine the distribution of plasma membrane glycoproteins. These conjugates can be viewed via electron microscopy.