Abstract: Methods for achieving complete sequence coverage of monoclonal antibodies by trypsin digestion and dual-column LC-MS system are provided. The disclosed method improves upon current techniques for standard peptide mapping.

Abstract: The present invention provides rapid, sensitive high-throughput methods and systems for characterizing peptides or proteins using affinity-based chromatography-coupled native mass spectrometry to improve manufacturing process of biopharmaceutical products, such as identifying impurities during antibody purification, monitoring post-translational modification variants during production, or characterizing drug-to-antibody ratio of antibody-drug conjugates. The separation profiles of the peptides or proteins are generated and compared to identify or qualify the peptides or proteins, wherein the separation profile is based on differential affinity binding.

Abstract: Systems and methods to characterize dimerization interfaces at the subdomain level of a protein are provided. An exemplary method includes digesting a protein dimer sample into subdomains, labeling the digested protein sample, isolating labeled dimeric and monomeric subdomain fragments, and peptide mapping the labeled sample to determine where the dimer fragments are labeled and where the dimer fragments are not labeled. Regions that show decreased labeling extents in the dimer fraction than that in the monomer fraction are likely involved or in close proximity to the dimerization interface.

Abstract: Methods of determining the stoichiometry of a viral capsid and/or determining the heterogeneity of protein components in a viral capsid are disclosed.

Abstract: Methods and system for characterizing a protein using a chromatographic system having a protein A chromatography resin and electrospray ionization mass spectrometer run under native conditions are provided.

Abstract: Methods and system for identification of dimer species using online chromatography and electrospray ionization mass spectrometry are provided. Also provided are methods and system for quantitation of heterodimer species using immunoprecipitation and liquid chromatography-mass spectrometry.

Abstract: Systems and methods to characterize dimerization interfaces at the subdomain level of a protein are provided. An exemplary method includes digesting a protein dimer sample into subdomains, labeling the digested protein sample, isolating labeled dimeric and monomeric subdomain fragments, and peptide mapping the labeled sample to determine where the dimer fragments are labeled and where the dimer fragments are not labeled. Regions that show decreased labeling extents in the dimer fraction than that in the monomer fraction are likely involved or in close proximity to the dimerization interface.

Abstract: Compositions and methods for analyzing disulfide bonds are provided. An exemplary method includes preparing peptide standards having no disulfide bonds, scrambled disulfide bond peptide standards, and native disulfide bond peptide standards according to the sequence of the region of the protein drug product that includes the disulfide bond, digesting a sample of protein drug product into peptides, separating the protein drug product peptides, analyzing the protein drug product peptides and the peptide standards, identifying scrambled and native disulfide bond peptides by retention time, and quantifying the level of scrambled disulfide bond peptides.

Abstract: Methods and system for identifying and quantifying antibody fragments and identifying the site of fragmentation on an antibody are provided herein.

Abstract: The present disclosure pertains to method and system of characterizing a protein using an electrospray ionization source.

Abstract: Methods and system for identifying and/or quantifying a protein are provided herein.

Abstract: Methods of determining the stoichiometry of a viral capsid and/or determining the heterogeneity of protein components in a viral capsid are disclosed.

Abstract: Systems and methods to characterize dimerization interfaces at the subdomain level of a protein are provided. An exemplary method includes digesting a protein dimer sample into subdomains, labeling the digested protein sample, isolating labeled dimeric and monomeric subdomain fragments, and peptide mapping the labeled sample to determine where the dimer fragments are labeled and where the dimer fragments are not labeled. Regions that show decreased labeling extents in the dimer fraction than that in the monomer fraction are likely involved or in close proximity to the dimerization interface.

Abstract: Systems and methods for characterizing size and charge variant protein drug product impurities are provided.

Abstract: Compositions and methods for identifying glucuronylated protein drug products are provided.

Abstract: Methods for achieving complete sequence coverage of monoclonal antibodies by trypsin digestion and dual-column LC-MS system are provided. The disclosed method improves upon current techniques for standard peptide mapping.

Abstract: Systems and methods for characterizing low molecular weight (LMW) protein drug product impurities are provided. One embodiment uses hydrophilic interaction chromatography (HILIC) coupled to mass spectrometry analysis. After removal of the N-linked glycans from the protein drug product, for example an antibody drug product, the elution of LMW impurities from the HILIC column was determined by the size of the molecular weight species. In some embodiments, the HILIC separation is performed under denaturing conditions, making the detection of LMW forms using this method highly comparable to both SDS-PAGE and CE-SDS methods. LMW drug product impurities include, but are not limited to light chain, half antibody, H2L, H2, HL, HC, peptide backbone-truncated species, and combinations thereof.