An enzyme-linked immunosorbent assay for detecting proteolytic activity of hepatitis C virus proteinase

An ELISA method for the quantitation in vitro of HCV serine proteinase activity was developed. A peptide substrate, Ac-Gly-Glu-Ala-Gly-Asp-Asp-Ile-Val-Pro-Cys-Ser-Met-Ser-Tyr-Thr-Trp-Thr-L ys (biotin) -OH (Sub-1), was hydrolyzed by a recombinant NS3 proteinase fused with maltose binding protein (MBP-NS3) into a product with a free amino moiety at the N-terminus. The product was immobilized, and the amino moiety was analyzed by digoxigenin labeling followed by immunological reaction with anti-digoxigenin-alkaline phosphatase conjugate and then the colorimeteric reaction. This method is suited for the high throughput screening of inhibitors, and the screening can be accelerated by automatic operation.