Protease, Serine 1 (PRSS1) is a digestive enzyme primarily produced in the pancreas as an inactive zymogen (trypsinogen). When activated to trypsin, it plays a key role in protein digestion by cleaving peptide bonds. Mutations in PRSS1 are linked to hereditary pancreatitis due to premature trypsin activation. PRSS1 can cleave albumin (ALB), the major plasma protein, potentially altering its structure and function during inflammatory conditions or pancreatic disorders.Thus a functional ELISA assay was conducted to detect the interaction of recombinant human PRSS1 and recombinant human ALB. Briefly, PRSS1 was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to ALB-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-PRSS1 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 PRSS1 and recombinant human ALB was shown in Figure 1, the EC50 for this effect is 0.24ug/mL.