Ribonuclease b rnase b from bovine pancreas

Carbon nanoparticles (particle size less than 100 nm and specific surface area higher than 100 m²/g), ribonuclease B (RNase B) from bovine pancreas, fetuin from fetal bovine serum, human alpha-1 acid glycoprotein (AGP), human serum from human male AB plasma, 2,5dihydroxybenzoic acid (DHB), and iodomethane were purchased from Sigma-Aldrich (St. Louis, MO). Microspin columns were purchased from Harvard Apparatus (Holliston, MA) and PNGase F with 10×G7 reaction buffer (0.5 M sodium phosphate) was obtained from New England Biolabs (Ipswich, MA). HPLC grade ethanol, acetonitrile (ACN), and water were used for sample preparation and were purchased from Sigma-Aldrich (St. Louis, MO).

Acetic acid, acetonitrile, ammonium acetate, and ammonium bicarbonate were obtained from Fisher Scientific (Pittsburgh, PA). Formic acid (FA), N,N-dimethylaniline (DMA), maltooctose, maltodextrin, and ribonuclease B (RNase B) from bovine pancreas were purchased from Sigma-Aldrich (St. Louis, MO). 2,5-Dihydroxybenzonic acid (99%, DHB) was from Acros Organics (Geel, Belgium). Dithiothreitol (DTT) and PNGase F were from Promega (Madison, WI). Microcon filters YM-30 were purchased from Merck Millipore (Billerica, MA). Human serum powder, LC/MS grade isopropanol (IPA), acetonitrile (ACN), methanol (MeOH), and water were from Fisher Scientific (Pittsburgh, PA). The hydrazide labeling reagents, light tag 2-hydrazino-4,6-bis-(diethylamino)-s-triazine (HDEAT) and heavy tag 2-hydrazino-4,6-bis-(d10-diethylamino)-s-triazine (d₂₀-HDEAT), were synthesized according to a protocol described previously [31 ].