title: Differences in electrophoretic behavior between linear and branched PEG-conjugated proteins.
abstract: The objective of this study was to characterize the differences in electrophoretic behavior between linear and branched PEG-conjugated proteins. Human growth hormone and alpha-lactalbumin modified by linear or branched PEGs with molecular weight of 10 kDa were analyzed by SEC, MALDI-TOF MS, SDS-PAGE, and microchip CGE (MCGE). Chromatographic and mass spectrometric differences between the linear and branched PEG-proteins on SEC and MALDI-TOF MS were small, but their electrophoretic behaviors on SDS-PAGE and MCGE were significantly different. In particular, MCGE showed significant differences in the peak width and the migration times of linear and branched PEG-proteins, in which the branched PEG-proteins exhibited a narrower peak and longer migration time than the linear PEG-proteins. This phenomenon may explain the longer circulation half-life for the branched PEG-proteins observed in previously reported in vivo studies. Consequently, this study indicates that MCGE may be a valuable tool for differentiating linear and branched PEG-proteins.
authors.affiliation: College of Pharmacy and Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu, Republic of Korea.
authors.forename: Eun Ji
authors.initials: EJ
authors.lastname: Park
authors.forename: Myung
authors.initials: M
authors.lastname: Sun Kim
authors.forename: Hye
authors.initials: H
authors.lastname: Suk Lee
authors.forename: Kang
authors.initials: K
authors.lastname: Choon Lee
authors.forename: Dong
authors.initials: D
authors.lastname: Hee Na
mesh_terms: D019075:Electrophoresis, Capillary / Q000379:methods*; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods*; D008958:Models, Molecular; D011092:Polyethylene Glycols / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D011506:Proteins; D011092:Polyethylene Glycols
keywords: Branched PEG; Microchip CGE; PEG-protein conjugates; PEGylation