Pepsin Digestion for LC-MS/MS Peptide Mapping of a Trypsin Resistant Antibody

摘要

Pepsin digestion for peptide mapping is a rapid, effective alternative method for proteins that resist tryptic digestion. The method is simple and fast, taking only two hours and a minimum of steps. Regions of the antibody that were poorly digested with trypsin were elucidated with the pepsin map. Heterogeneity in the digestion is the major drawback. The pattern is consistent, cleaving primarily after V, L, Y, F and W, but also M, E, Q and others. This produced multiple overlapping peptides covering the region of interest. The drug conjugation for ADCs remained intact during digestion.