Adrenomedullin (ADM) is a peptide hormone first discovered in 1993 in pheochromocytoma. Although AM is highly expressed in the adrenal glands, heart, lungs, and kidneys, vascular endothelium and smooth muscle are thought to be the main source of plasma AM. It is a 52 aa peptide with several functions, including vasodilation, regulation of hormone secretion, promotion of angiogenesis, and antimicrobial activity. The antimicrobial activity is antibacterial, as the peptide has been shown to kill E. coli and S. aureus at low concentration. Receptor activity-modifying protein 2 can transports the calcitonin gene-related peptide type 1 receptor (CALCRL) to the plasma membrane. Acts as a receptor for adrenomedullin (AM) together with CALCRL. Thus a functional binding ELISA assay was conducted to detect the interaction of recombinant mouse ADM and recombinant human RAMP2. Briefly, ADM was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to RAMP2-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-ADM 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 mouse ADM and recombinant human RAMP2 was shown in Figure 1, the EC50?for this effect is 0.16 ug/mL.