E. coli lysate containing recombinant TEV protease was loaded on to a 4-20% gradient gel for separation. After electrophoresis, the gel was blocked with 1% BSA in TBS for 30min at ambient. The membrane was probed with the primary antibody at a 1:1,000 dilution in 1%BSA/TBS overnight at 4° C. For detection HRP conjugated Gt-a-Rabbit IgG was used at a 1:40,000 dilution for 30 min at ambient and data generated with FemtoMax enhanced chemiluminescent reagent Images were captured using BioRad Versadoc 4000MP Imaging System.