Ulex europaeus agglutinin (UEA I+II) is fractionated consists of two hemagglutinins (UEA I and UEA II). The two lectins can be separated by salt or ethanol precipitation. Both have been sequenced and are homologous with each other, as well as homologous with other legume lectins of various specificities. Carbohydrate-binding peptides have been isolated for each lectin after peptidase digestion, and these peptides also exhibit homology with other such peptides. UEA I interacts specifically with blood group H type 2 antigen, which is expressed in individuals with type O blood and to a lesser degree in individuals with type A or B blood. UEA II is not blood group specific but the best inhibitors are the H type oligosaccharides.