Figure 3: Peptide-based Sandwich ELISA-like assay (Sandwich pep- ELISA). In this experiment, the complete sandwich construct (pp2 + CatE + pp1015) and incomplete sandwich construct (CatE + pp1015 without pp2) were tested against the wild and the CatE-gene knockout rat plasma samples. The primary peptidepep 1 (pp2) was immobilized on to the surface of the microplate and then CatE was bound to pep 1 or not. Next, the secondary peptide pep 2 (pp1015) combined with an enzyme horse-radish peroxidase was added, bound to CatE, and then washed to remove the unfixed peroxidase. Note that in this case, CatE works as only a bridge between two peptides and does not work as an enzyme. Statistics were taken from 3 trials.