Lens culinaris agglutinin is composed of four subunits - two of about 17 kDa and two of 8 kDa. LCA recognizes sequences containing α-linked mannose residues but recognizes additional sugars as part of the receptor structure, giving it a narrower specificity than Con A. An α-linked fucose residue attached to the N-acetylchitobiose portion of the core oligosaccharide significantly enhances affinity. By exploiting this narrower specificity, glycoproteins and glycopeptides can be subfractionated with LCA after initial isolation with Con A. LCA has been found to be one of the most effective agents in preventing skin allograft rejection in model systems. LCA has been used to purify numerous glycoproteins, including immunoglobulins, histocompatibility antigens, and α2-macroglobulin.