Integrin Beta 1 (ITGb1), also known as CD29, is a fundamental subunit of the integrin family of adhesion receptors. It is ubiquitously expressed on cell surfaces and can heterodimerize with various alpha subunits to form distinct integrins. These heterodimers are crucial for mediating bidirectional signaling between the cell and its extracellular matrix (ECM), influencing essential processes such as cell adhesion, migration, proliferation, and survival. ITGb1 binds to ECM proteins like fibronectin and laminin, playing a vital role in embryonic development, tissue repair, and immune responses. Specifically, ITGb1 non-covalently associates with Integrin Alpha 3 (ITGa3) to form a functional receptor for laminin-5 in epithelial cells.To detect the activity of recombinant ITGb1, a functional ELISA assay was performed to evaluate the interaction between recombinant rat ITGb1 and recombinant mouse ITGa3. Briefly, biotin-linked ITGb1 were diluted serially in PBS, with 0.01% BSA (pH 7.4). Duplicate samples of 100µl were then transferred to ITGa3-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 50µl stop solution to the wells and read at 450nm immediately. The binding activity of recombinant rat ITGb1 and recombinant mouse ITGa3 was shown in Figure 1, the EC50 for this effect is 0.73µg/mL.