E-Cadherin, also known as Uvomorulin in the mouse and rat, is a 120?kDa member of the Cadherin family of cell surface glycoproteins that mediate cell adhesion. Human E-Cadherin shares 81%?amino acid sequence identity with the rat and mouse proteins. It is a single-pass transmembrane protein that mediates calcium-dependent epithelial cell adhesion. As E-cadherin has the function of cell adhesion, we measure the activity of recombinant human E-cadherin by the ability of the immobilized protein to support the adhesion of MCF7 human breast cancer cells. When 5 x 104?cells/well are added to different concentrations of recombinat human E-cadherin coated plates, cells will adhere after 2?hour incubation at 37 ℃. The adhesion of MCF7 after 2?hour incubation at 37 ℃ observed by inverted microscope was shown in Figure 1. Cell adherent was in a dose dependent manner, the result was shown in Figure 2, the EC50 was 0.19 ug/ml.