title: Identification of N-terminal modification for recombinant monoclonal antibody light chain using partial reduction and quadrupole time-of-flight mass spectrometry.
abstract: Since most recombinant monoclonal antibodies (mAbs) contain glutamic acid or glutamate at their N-terminus, cyclization of these residues to form pyroglutamate is an important degradation pathway that often occurs in therapeutic mAb development. In this work, a rapid method was developed to determine pyroglutamate at the N-terminus of mAb light chain by liquid chromatography coupled with electrospray ionization on a quadrupole time-of-flight mass spectrometer (QTOF). High levels of pyroglutamate were found at the N-terminus of the light chain of a typical recombinant mAb. The quantitative results were comparable to those obtained with a more conventional peptide mapping method. The direct method outlined here can be used to evaluate the impact of N-terminal cyclization during the processing of recombinant mAbs.
authors.affiliation: Department of Pharmaceutics, Amgen, Inc., Thousand Oaks, CA 91320, USA. leiy@amgen.com
authors.forename: Lei
authors.initials: L
authors.lastname: Yu
authors.forename: Richard L
authors.initials: RL
authors.lastname: Remmele
authors.forename: Bing
authors.initials: B
authors.lastname: He
mesh_terms: D000911:Antibodies, Monoclonal / Q000032:analysis* / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004355:Drug Stability; D007147:Immunoglobulin Light Chains / Q000032:analysis / Q000737:chemistry; D010084:Oxidation-Reduction; D011994:Recombinant Proteins / Q000032:analysis* / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D000911:Antibodies, Monoclonal; D007147:Immunoglobulin Light Chains; D011994:Recombinant Proteins