Glypican 2 (GPC2), a member of glypican (GPC) family genes, produces proteoglycan with a glycosylphosphatidylinositol anchor. Level of the various glypicans changes in a stage and tissue specific manner. Syndecan-2 is expressed in cells of mesenchymal origin, neuronal and epithelial cells, and is the predominant syndecan expressed during embryonic development. Human Syndecan-2 is synthesized as a 201 amino acid (aa) core protein with an 18 aa signal sequence, a 126 aa extracellular domain (ECD), a 25 aa transmembrane region and a 32 aa cytoplasmic tail. The human ECD of Syndecan-2 contains three closely-spaced consensus Ser-Gly sequences for the attachment of HS side chains. It shares 76%, 73%, 87%, 78% and 63% aa identity with the ECD of mouse, rat, bovine,?canine and chicken Syndecan-2, respectively. SDC1 has been identified as an interactor of GPC2, thus a functional binding ELISA assay was conducted to detect the interaction of recombinant human GPC2 and recombinant bovine SDC1. Briefly, biotin-linked GPC2 were diluted serially in PBS, with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to SDC1-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST 3 times and incubation with Streptavidin-HRP for 30min, then wells were aspirated and washed 5 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37℃. Finally, add 50 μl stop solution to the wells and read at 450 nm immediately. The binding activity of recombinant human GPC2 and recombinant bovine SDC1 was shown in Figure 1, the EC50?for this effect is 195.6 ng/mL.