Updated project metadata. In this study, multiple enzyme digestion method was used to enhance the peptide sequence coverage of cytotoxin to characterize its epitope properties. This epitope excision method exhibits no preference for either consecutive or assembled epitopes, based on the specific binding between an antibody and cytotoxin. Following the binding of cytotoxin to its respective antibody, the epitope peptide sequences were shielded from enzymatic proteolysis experiment. Thesedigested peptides were then identified by LC-MS.