Deamidation is a chemical reaction to remove the functional groups of amide from organic compounds. For proteins, deamidation can occur in vitro or in vivo as post-translational modification, where asparagine (Asn) and glutamine (Gln) residues are converted into aspartic acid (Asp) and glutamic acid (Glu) respectively. Recent advances in sample preparation methods, chromatographic separation, mass spectrometer technology, and data processing have for the first time enabled the accurate and reliable characterization of protein modifications in complex biological samples, yielding important new data on how deamidation occurs across the entire proteome of human cells and tissues.
Figure 1. The chemical reaction of asparagine deamidation process. ( L, Jia. Y, Sun. 2017)
In recent years, protein-based drugs, especially monoclonal antibodies, are one of highlights of drug discovery, because they generally offer high target specificity with low side effects. Unlike small molecule drugs, therapeutical products are more susceptible to various modifications during the procedures of manufacturing, shipping, and storage. Despite the maturation and robustness of biosynthesis platforms, specific product-related modifications may be present in the final drug products, at various levels, which potentially affect safety and efficacy after dosing. Deamidation of Asn or Gln and isomerization of Asp represent routine degradation pathways for monoclonal antibodies. The spontaneous non-enzymatic deamidation, or isomerization may induce the alteration of protein properties through the introduction of negative charges, and/or the insertion of a methylene group in the peptide backbone, leading to reduced biological activity and product stability, and increase of immunogenicity. It is an intrinsic part of determining the critical quality attributes and appropriate control strategy for therapeutic monoclonal antibodies.
Protein Deamidation Analysis at Creative Proteomics
At Creative Proteomics, we have developed a professional platform for protein oxidation analysis that contains various techniques, including but not limited to:
Our experienced analysts and technicians can help you to not only detect and identify deamidation sites, but also estimate the percentage of deamidation in specific sites. Creative Proteomics has developed a rapid peptide spectrum analysis method to generate robust and repeatable analysis results. Creative Proteomics's technology in characterization of therapeutic protein deamidation is quite mature and can provide you with good technical services. If you have any questions or specific needs, don’t hesitate to contact us.
1. L, Jia. Y, Sun. Protein asparagine deamidation prediction based on structures with machine learning methods. Plos one. 2017, 12(7): e0181347.