Calcitonin gene-related peptide (CGRP) is a highly potent vasoactive peptide released from sensory nerves. CGRP is a 37-amino acid and it has two major forms (α and β). It belongs to a group of peptides that all act on an unusual receptor family. These receptors consist of calcitonin receptor-like receptor (CLR) linked to an essential receptor activity modifying protein (RAMP) that is necessary for full functionality. Thus a functional binding ELISA assay was conducted to detect the interaction of recombinant rat CGRP and recombinant human RAMP2. Briefly, CGRP 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-CGRP 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 450/630 nm immediately. The binding activity of recombinant rat CGRP and recombinant human RAMP2 was shown in Figure 1, the EC50 for this effect is 0.06 ug/mL.