title: Characterization of the basic charge variants of a human IgG1: effect of copper concentration in cell culture media.
abstract: We report a case study of an IgG1 with a unique basic charge variant profile caused by C-terminal proline amidation on either one or two heavy chains. The proline amidation was sensitive to copper ion concentration in the production media during cell culture: the higher the Cu ( 2+)  ion concentration, the higher the level of proline amidation detected. This conclusion was supported by the analysis of samples that revealed direct correlation between the proline amidation level observed from peptide maps and the level of basic peaks measured by imaged capillary isoelectric focusing and a pH gradient ion-exchange chromatography method. The importance of these observations to therapeutic antibody production is discussed.
authors: Department of Pharma Technical Development, Genentech, Oceanside, CA, USA.
authors: Timothy
authors: T
authors: Kaschak
authors: Daniel
authors: D
authors: Boyd
authors: Franklin
authors: F
authors: Lu
authors: Gayle
authors: G
authors: Derfus
authors: Brian
authors: B
authors: Kluck
authors: Bartek
authors: B
authors: Nogal
authors: Craig
authors: C
authors: Emery
authors: Christie
authors: C
authors: Summers
authors: Kai
authors: K
authors: Zheng
authors: Robert
authors: R
authors: Bayer
authors: Ashraf
authors: A
authors: Amanullah
authors: Boxu
authors: B
authors: Yan
mesh_terms: D000577:Amides / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016466:CHO Cells; D002852:Chromatography, Ion Exchange; D003300:Copper / Q000032:analysis / Q000494:pharmacology*; D006224:Cricetinae; D003470:Culture Media / Q000737:chemistry; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007525:Isoelectric Focusing; D010449:Peptide Mapping; D011392:Proline / Q000737:chemistry; D018892:Proton-Motive Force
chemical_list: D000577:Amides; D000911:Antibodies, Monoclonal; D003470:Culture Media; D007074:Immunoglobulin G; D003300:Copper; D011392:Proline