Ulex europaeus agglutinin (UEA I+II) is affinity purified 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.Cy5, when bound to Ulex europaeus Lectin (UEA I+II), can show the binding pattern of this lectin in cellular imaging and flow cytometry. The excitation wavelength required for Cy5 to fluoresce is high enough to avoid overlap with most other fluorochromes, making it useful for dual-labeling experiments. Because of this high excitation, there is typically less background from autofluorescence of biological specimens.