Characterization of Soluble Non-covalent Complexes between Bovine Serum Albumin and β-1,2,3,4,6-Penta-O-galloyl- d -glucopyranose by MALDI-TOF MS

β-1,2,3,4,6-Penta- O -galloyl- d -glucopyranose (PGG) and soluble complexes of PGG with bovine serum albumin (BSA) were characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). PGG was also characterized by electrospray ionization mass spectrometry (ESI-MS). Similar fragmentation patterns of PGG were found in ESI-MS and MALDI-TOF MS. The apparent stoichiometries of non-covalent BSA−PGG complexes were determined by MALDI-TOF MS.