title: Mass spectrometric distinction of in-source and in-solution pyroglutamate and succinimide in proteins: a case study on rhG-CSF.
abstract: Formation of cyclic intermediates involving water or ammonia loss is a common occurrence in any reaction involving terminal amines or hydroxyl group containing species. Proteins that have both these functional groups in abundance are no exception, and presence of amino acids such as asparagine, glutamines, aspartic acids, and glutamic acids aid in formation of such intermediates. In the biopharma scenario, such intermediates lead to product- or process-related impurities that might be immunogenic. Mass spectroscopy is a powerful technique that is used to decipher the presence and physicochemical characteristics of such impurities. However, such intermediates can also form in situ during mass spectrometric analysis. We present here the detection of in-source and in-solution formation of succinimide and pyroglutamate in the protein granulocyte colony stimulating factor. We also propose an approach for quick differentiation of such in-situ species from the tangible impurities. We believe that this will not only reduce the time spent in unambiguous identification of succinimide- and/or pyroglutamate-related impurity in bio-pharmaceutics but also provide a platform for similar studies on other impurities that may form due to stabilized intermediates.
authors.affiliation: Molecular Characterization Laboratory, Biocon Research Ltd., Bangalore, Karnataka, India.
authors.forename: Mukesh
authors.initials: M
authors.lastname: Kumar
authors.forename: Amarnath
authors.initials: A
authors.lastname: Chatterjee
authors.forename: Anand P
authors.initials: AP
authors.lastname: Khedkar
authors.forename: Mutyalasetty
authors.initials: M
authors.lastname: Kusumanchi
authors.forename: Laxmi
authors.initials: L
authors.lastname: Adhikary
mesh_terms: D016179:Granulocyte Colony-Stimulating Factor / Q000737:chemistry*; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D008958:Models, Molecular; D010446:Peptide Fragments / Q000032:analysis / Q000145:classification; D011761:Pyrrolidonecarboxylic Acid / Q000032:analysis* / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry*; D013388:Succinimides / Q000032:analysis* / Q000737:chemistry; D014357:Trypsin / Q000737:chemistry
chemical_list: D010446:Peptide Fragments; D011994:Recombinant Proteins; D013388:Succinimides; C032620:succinimide; D016179:Granulocyte Colony-Stimulating Factor; D014357:Trypsin; D011761:Pyrrolidonecarboxylic Acid