Annexin A1 (ANXA1), also known as lipocortin I, belongs to the annexin family of Ca2 -dependent phospholipid-binding proteins that have a molecular weight of approximately 35,000 to 40,000 and are preferentially located on the cytosolic face of the plasma membrane. Annexin A1 protein has an apparent relative molecular mass of 40kDa with phospholipase A2 inhibitory activity. Besides, S100 Calcium Binding Protein A11 (S100A11) has been identified as an interactor of ANXA1, thus a binding ELISA assay was conducted to detect the interaction of recombinant human ANXA1 and recombinant human S100A11. Briefly, ANXA1 were diluted serially in PBS, with 0.01% BSA (pH 7.4). Duplicate samples of 100μL were then transferred to S100A11-coated microtiter wells and incubated for 2h at 37℃. Wells were washed with PBST and incubated for 1h with anti-ANXA1 pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody, wells were aspirated and washed 3 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 ANXA1 and S100A11 was shown in Figure 1, and this effect was in a dose dependent manner.
Figure. The binding activity of ANXA1 with S100A11.