PEGylation Analysis and Method Verification

BOC Sciences provides PEGylation analysis and method verification services, which mainly focus on the PEGylation process of proteins and peptides. Our services focus on the analysis and verification of PEGylation sites, as well as PEGylation conditions and efficiencies.

At present, the commonly used protein-conjugated PEGylation processes can be roughly classified into two types, namely, a liquid phase synthesis process and a column synthesis process. The general procedure is to mix the reagents together in a suitable buffer solution, mix at the appropriate temperature, and then separate and purify the desired product using appropriate techniques based on its physicochemical properties, including ion exchange chromatography (IEX), six-layer exclusion chromatography (SEC), hydrophobic interaction chromatography (HIC), and membrane phase or aqueous phase systems. However, in the synthetic process, prolonged contact between the reactive species and the product results in multiple conjugations and the production of many PEG isomers, thus a heterogeneous product mixture is produced. What's more, multi-step purifications and downstream treatments can significantly reduce the overall yield.

PEGylation of proteins or other molecules is not a simple process. There are many possibilities for the site modification and amount of PEG modification, and the PEGylation method must be adjusted to the chemistry of the particular protein. Also it needs to consider the more profound effects of the modified protein in the body. It is necessary and very important to know the detailed structural characterization of PEGylation of proteins and peptides, including PEGylation sites, the number of attached PEGs, the average degree of modification, the relative content of proteins with different degrees of modification and PEG heterogeneity. These types of data ensure the quality control for biomolecules and are required for registering these molecules as biopharmaceuticals.

PEGylation was approved by the US Food and Drug Administration (FDA) in 1990, and the first PEGylated Adagen bovine adenosine deaminase produced by Enzon Pharmaceuticals was used to treat X-linked severe immunodeficiency disease (SCID). Since then, more than a dozen of PEGylated products have been approved, and now more products are still under development. The development of PEGylation technology has proved its pharmacological advantages in the past forty years, but this technology does not have commercial versatility. High-yield, highly specific PEGylation therapeutic products are important areas for future product and technology research and development.

Figure 1. Strategy for the determination of PEGylation sites and positional isomers.Figure 1. Strategy for the determination of PEGylation sites and positional isomers. (Bailon, P., & Won, C.-Y., 2009)

BOC Sciences has developed a professional platform for PEGylation analysis including various techniques. Fluorescamine method is used to determine the average degree of modification by measuring the fluorescence value excited by the protein mixture. Spectrophotometry is a highly sensitive method used to determine the content. Chromatography is used to determine the average molecular weight and average degree of modification of the mixture. Mass specrometry (MS) is used to determine the modification site and the degree of modification.

BOC Sciences provides sophisticated PEGylation analysis and method verification services to help you characterize PEGylation of proteins and peptides at specific sites. We will be your excellent partner. Please contact us immediately if you have any questions or specific needs.


  1. Fee, C. J., & Van Alstine, J. M., 2006. PEG-proteins: Reaction engineering and separation issues. Chemical Engineering Science, 61 (3), pp. 924–939.
  2. Fee, C. J., 2009. Protein conjugates purification and characterization. PEGylated Protein Drugs: Basic Science and Clinical Applications, pp. 113–125.
  3. Bailon, P., & Won, C.-Y., 2009. PEG-modified biopharmaceuticals. Expert Opinion on Drug Delivery, 6 (1), pp. 1–16.

Online Inquiry

  • Verification code



  • International: 1-631-504-6093
  • US & Canada (Toll free): 1-844-BOC(262)-0123
  • International: 1-631-504-6093
  • Email:
  • 45-16 Ramsey Road, Shirley, NY 11967, USA
  • Europe


    © 2020 BOC Sciences. All rights reserved.