A Mass Spectrometric Characterization of Light-Induced Modifications in Therapeutic Proteins

During the development of a therapeutic protein, its quality attributes that pertain to the primary structure must be appropriately characterized, commonly by LC-MS/MS peptide mapping experiments. Extracting attribute information from LC-MS/MS data requires knowledge of the attribute of interest. Therefore, it is important to understand all potential modifications on the therapeutic proteins. In this work, we performed UV and visible light irradiation experiments on several therapeutic proteins, with or without the presence of a photosensitizer. Light-induced modifications were detected and characterized by tryptic digestion followed by LC-MS/MS analysis. A list of potential light-induced modifications, with their respective mass changes, was obtained. These modifications are primarily on methionine, tryptophan, histidine, cysteine, tyrosine and phenylalanine residues. Many of these modifications have not been previously reported on therapeutic proteins. Our findings therefore provide a database of potential light-induced modifications that would enable the routine characterization of light-induced modifications on therapeutic proteins. (C) 2022 The Authors. Published by Elsevier Inc. on behalf of American Pharmacists Association.

Automated summary

This study characterizes light-induced modifications on therapeutic proteins through irradiation experiments and identifies a list of potential modifications. The findings provide a database for routine characterization of light-induced modifications on therapeutic proteins.