TY - CONF A1 - Döring, Sarah T1 - Optimization of surface-functionalized particles for improved antibody digestion N2 - Therapeutic monoclonal antibodies are the fastest-growing group of biological agents which generated a yearly turnover of USD 210 billion in 2022 and whose sales are expected to grow by 10% annually over the next 10 years. With steadily increasing market importance, analytical methods for reliable quantification of therapeutic antibodies also become more and more relevant. Liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) has become the main technology for antibody quantification. This approach, however, requires enzymatic digestion of the intact protein into peptides, for which a wide range of different protocols exists that often lead to different results depending on the digestion procedure or trypsin variants used. In particular, the amount and type of detergents added for protein unfolding prior to digestion is known to create significant bias in measurement results. The overall goal of the presented project is the application of novel thermostable and surface-functionalized trypsin particles for improved antibody digestion. Specifically, a trypsin-variant described in the literature exhibiting increased activity and thermal stability above 80°C, will be examined. The application of this enzyme should allow to perform digestion at elevated temperatures where the protein is naturally unfolding thereby increasing enzyme accessibility without the need for detergents. Furthermore, we will immobilize the thermostable trypsin onto the surface to further enhance enzyme stability, prevent self-digestion, and enable separation of trypsin from target peptides before LC–MS/MS analysis. As an immobilization platform, cheap and non-porous corundum particles will be used as these show high chemical stability and low levels of interaction of matrix proteins with the functionalized surface. adsorption. In a multidisciplinary collaboration with the SALSA Photonics Lab, we will investigate the characteristics of covalent enzyme binding and unspecific peptide binding using an interface-sensitive analytical tool, vibrational sum-frequency generation (VSFG) spectroscopy. The insights gained will not only lead to new competencies in peptide and enzyme surface analysis using VSFG spectroscopy in SALSA but will also significantly contribute to optimizing antibody quantification. T2 - SALSA STF24 Kick-Off Meeting CY - Berlin, Germany DA - 11.04.2024 KW - Antibody Quantification KW - Vibrational Sum-Frequency Generation Spectroscopy KW - LC-MS/MS KW - Enzyme Immobilisation KW - Corundum PY - 2024 AN - OPUS4-59864 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - INPR A1 - Döring, Sarah A1 - Weller, Michael G. A1 - Reinders, Yvonne A1 - Konthur, Zoltán A1 - Jaeger, Carsten T1 - Challenges and Insights in Absolute Quantification of Recombinant Therapeutic Antibodies by Mass Spectrometry: An Introductory Review N2 - This review describes mass spectrometry (MS)-based approaches for the absolute quantification of therapeutic monoclonal antibodies (mAbs), focusing on technical challenges in sample treatment and calibration. Therapeutic mAbs are crucial for treating cancer, inflammatory, infectious, and autoimmune diseases. We trace their development from hybridoma technology and the first murine mAbs in 1975 to today’s chimeric and fully human mAbs. With increasing commercial relevance, absolute quantification of mAbs, traceable to SI units, has attracted attention from science, industry, and national metrology institutes (NMIs). Quantification of proteotypic peptides after enzymatic digestion using liquid chromatography-tandem mass spectrometry (LC-MS/MS) has emerged as the most viable strategy, though methods targeting intact mAbs are still being explored. We review peptide-based quantification, focusing on critical experimental steps like denaturation, reduction, alkylation, choice of digestion enzyme, and selection of signature peptides. Challenges in amino acid analysis (AAA) for quantifying pure mAbs and peptide calibrators, along with software tools for targeted MS data analysis, are also discussed. Short explanations within each chapter provide newcomers an overview of the field’s challenges. Finally, we discuss prospects and limitations of developing standardized protocols and certified reference materials (CRMs) and suggest future applications of newer technologies for the absolute quantification of therapeutic antibodies. KW - Antibody KW - Mass spectrometry KW - Absolute quantification KW - Metrology KW - Reference products PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621841 DO - https://doi.org/10.20944/preprints202412.1081.v1 SP - 1 EP - 22 PB - MDPI AN - OPUS4-62184 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Döring, Sarah T1 - Novel Trypsin-functionalized Corundum Particles for Improved Antibody Digestion N2 - Therapeutic monoclonal antibodies are the fastest-growing class of biological agents and the development of reliable analytical methods for their quantification is becoming increasingly important. Liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) represents one of the leading technologies for antibody quantification. The serin protease trypsin has emerged as the gold standard enzyme for digesting intact protein into peptides for this approach. However, many protocols exist that often lead to different results. However, many protocols exist that often lead to different results depending on the digestion procedure. In particular, the type and amounts of detergents added during sample preparation for protein unfolding before digestion is known to create undesirable structure modifications of proteins (e.g. carbamylation) and significant bias in measurement results by inhibiting enzyme activity. The source and nature of the enzyme itself can also have an influence, whereby immobilized variants are increasingly being used to improve their stability, minimize self-digestion and enable a higher substrate-enzyme ratio. Here, we explored the potential of a novel thermostable trypsin and surface-functionalized corundum particles for enhanced antibody digestion. For this purpose, the inactive proenzym was recombinantly produced in inclusion bodies of E. coli and successfully folded back into functional conformation via multi-stage dialysis using a cysteine-cystine redox system. After cleavage of the propeptide and purification of active variants, enzyme activity was comparable to commercially available trypsin product. In addition, produced trypsin showed increased thermal stability under typical digestion conditions compared to reference product. In solution digestion experiments of antibody have revealed that the thermostable variant demonstrates enhanced digestive efficacy compared to the wild type. Furthermore, APTES-silanization followed by polymerization of corundum surface prevent nonspecific protein adsorption during the protein digestion procedure and the immobilized enzyme still showed substrate activity after covalent binding. Compared to wild-type and a non-immobilized enzyme, the surface-functionalized thermostable variant showed increased activity at temperatures above 80°C. Thus, this novel type of trypsin particles promises to not only improve antibody digestion at high temperatures, but also to prevent self-digestion and enable the separation of trypsin from target peptides in LC–MS analysis. T2 - Adlershofer Forschungsforum CY - Berlin, Germany DA - 11.11.2024 KW - Antibody Quantification KW - Corundum KW - Enzyme Immobilization KW - LC-MS/MS PY - 2024 AN - OPUS4-61680 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Döring, Sarah T1 - Surface Immobilization of Thermostable Trypsin for Optimized Antibody Digestion N2 - Therapeutic monoclonal antibodies are the fastest-growing class of biological agents generating yearly sales of approx. USD 220 billion in 2023 which is expected to triple over the next decade. With the growing market significance of therapeutic antibodies, analytical methods allowing reproducible and metrologically traceable quantification need to be developed. In recent years, antibody quantification at the peptide level using liquid chromatography coupled with tandem mass spectrometry (LC-MS) has emerged as the leading technology. The serin protease trypsin has become the gold standard enzyme for digesting intact protein into peptides for this approach. However, many protocols exist that often lead to different results depending on the digestion procedure. In particular, the type and amount of detergents added during sample preparation for protein unfolding before digestion is known to create undesirable structure modifications of proteins (e.g. carbamylation) and significant bias in measurement results by inhibiting enzyme activity. The enzymes themselves can also have an influence, whereby immobilized variants are increasingly being used to improve their stability, minimize self-digestion and enable a higher substrate-enzyme ratio. Here, we studied the implementation of a thermostable and surface-functionalized trypsin-variant for improved antibody digestion. T2 - 23rd Human Proteome Organization World Congress CY - Dresden, Germany DA - 20.10.2024 KW - Antibody Quantification KW - Corundum KW - Enzyme Immobilization KW - LC-MS/MS PY - 2024 AN - OPUS4-61679 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Döring, Sarah T1 - Optimization of Polymer Interface: Novel Surface-functionalized Corundum Particles for Improved Antibody Digestion N2 - Therapeutic monoclonal antibodies are the fastest-growing class of biological agents and the development of reliable analytical methods for their quantification is becoming increasingly important. Liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) represents one of the leading technologies for antibody quantification. The serin protease trypsin has emerged as the gold standard enzyme for digesting intact protein into peptides for this approach. However, many protocols exist that often lead to different results. The talk will provide a brief introduction to the application of novel thermostable and surface-functionalized trypsin particles for improved antibody digestion as well as initial successes in polymer functionalization of the corundum surface to prevent nonspecific protein adsorption during the digestion procedure. T2 - SALSA Make and Measure 2024: Interfaces CY - Berlin, Germany DA - 11.09.2024 KW - Antibody Quantification KW - Recombinant Enzymes KW - LC-MS/MS KW - Enzyme Immobilisation KW - Surface Functionalisation KW - Corundum PY - 2024 AN - OPUS4-61041 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -