Pharmalyte 3 10

mAb-A was a purified monoclonal antibody Drug Substance produced in house and formulated at pH 6.0. Trypsin enzymes were obtained from Promega (Madison, WI, USA Cat# V5113). Lys-C was purchased from Fujifilm Wako (Osaka, Japan. Cat# SKR0971). Urea (OmniPur^®, Product# 29700) and Trizma^® hydrochloride solution (Cat# T7943) were obtained from Millipore Sigma (Billerica, MA, USA). LC–MS grade water (Cat# W6-1), acetonitrile (Cat# A955-500), formic acid (Cat# A117-50) and trifluoroacetic acid (Cat# A116-1AMP) were obtained from Fisher Chemical (Fair Lawn, NJ, USA). Bovine Serum Albumin (BSA, Cat# A2058-25G), Sodium phosphate dibasic (Cat# S3264-250G), sodium phosphate monobasic monohydrate (Cat# S5011-500G), and sodium chloride (Cat# S9625-1KG) and guanidine hydrochloride solution (Cat# G7294-100ML), and 4M urea (Cat# 51456-500G) were obtained from Sigma-Aldrich (St. Louis, MO, USA). Iodoacetamide (IAA, Cat# 90034) and dithiothreitol (DTT, Cat# 20291) were obtained from Thermo Fisher Scientific (Waltham, MA, USA). pI markers 7.05 (Cat# 046-032) and 9.99 (Cat# 046-034), 1% methyl cellulose (Cat# 101876), and 500 mM arginine (Cat #042-6910) were obtained from ProteinSimple (San Jose, CA, USA). Pharmalyte 3–10 was obtained from Cytiva (Uppsala, Sweden; Cat# 17045601).

Formic acid (FA), Dynamis™ medium and CD-CHO medium were purchased from Thermo Fisher Scientific (Pittsburg, PA, United States). Trifluoroacetic acid (TFA) was obtained from TCI (Shanghai, China). Dithiothreitol (DTT) was purchased from Adamas (Shanghai, China). Acetonitrile, iodoacetamide (IAM), urea, β-mercaptoethanol, guanidine hydrochloride, ammonium carbonate, goat anti-human IgG(Fab) and trypsin were purchased from Sigma-Aldrich (St. Louis, MO, United States). Lys-C was obtained from Wako (Osaka, Japan). Peptide:N-glycosidase F (PNGase F) were purchased from New England BioLabs (Ipswich, Massachusetts, United States). IgG Purity and Heterogeneity Kit were purchased from SCIEX (CA, United States). 1% Methyl Cellulose, 0.5%Methyl Cellulose, pI Marker 5.85, pI Marker 9.77 were purchased from Protein Simple (San Francisco, California, United States). Pharmalyte 3–10 was purchased from Cytiva (MA, United States). Epidermal Growth Factor Receptor (EGFR) was from SinoBiological (Beijing, China). The synthesized peptide was prepared by GenScript (Nanjing, China). All the reagents used in our experiments were reagent grade or higher purity.