Figure. Global characterization map of trastuzumab with majority of modifications annotated. Sequences that hide behind are unreachable, thus cannot be labeled. Each color band represents a proteolytic peptide. Color code represents average percentage of modifications of duplicated injections of single digestion. Peptides not detected were depicted grey (A). Frequency was calculated as number of modified amino acid divided by total number of this amino acid in trastuzumab (B). Propensity to chemical modifications is calculated as total percentage of modification divided by number of this modified amino acid (C). All figures above came from trastuzumab that was incubated with H2O2 and leachable metals at 25°C (±1°C) for 27 hours. *Gln H39 was determined to be 80% converted to pyro-glutamate on the C-terminus of tryptic peptide R.QAPGK.G [38, 42]. The deglycosylation site Asn H301 was not considered as deamidation in B and C