Meprin A Beta, also known as MEP1B, is a zinc-dependent metalloprotease that belongs to the astacin family. This protease can form oligomeric complexes, such as with Meprin A Alpha, and is predominantly expressed in the kidney, intestine, and immune cells. Meprin A Beta plays a crucial role in extracellular matrix remodeling, inflammatory responses, and cell adhesion by cleaving various substrates, including collagen, cytokines like IL-1β and IL-6, and adhesion molecules. It exists in both membrane-anchored and soluble forms.Besides,MMP9 has been identified as an interactor of MEP1B, thus a functional binding ELISA assay was conducted to detect the interaction of recombinant human MEP1B and recombinant bovine MMP9. Briefly, Matrix Metalloproteinase 9 (MMP9) was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to MMP9-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-MEP1B pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody for 1h at 37℃, 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 450/630nm immediately. The binding activity of recombinant human MEP1B and recombinant bovine MMP9 was shown in Figure 1, the EC50?for this effect is 0.029 μg/mL.