Rebridging disulphides: site-specific PEGylation by sequential bis-alkylation

  • Ji-Won Choi
  • Antony Godwin
  • Sibu Balan
  • Penny Bryant
  • Yuehua Cong
  • Estera Pawlisz
  • Manuchehr Porssa
  • Norbert Rumpf
  • Ruchi Singh
  • Keith Powell
  • Steve Brocchini
Part of the Milestones in Drug Therapy book series (MDT)


Site-specific PEGylation reagents have been developed that undergo thiol-specific bis-alkylation with the two cysteine sulphur atoms from a native accessible disulphide in proteins. The process for this approach of site-specific PEGylation involves two steps: (1) disulphide reduction to release the two thiols and (2) bis-alkylation of the PEG reagent to the two sulphur atoms to give a three-carbon bridge to which PEG is covalently attached. Mechanistically, the conjugation is thought to occur by a sequential, interactive bis-alkylation that requires functionalised PEG reagents that have a α, β-unsaturated β′-mono-sulphone moiety. Competitive reactions can be effectively suppressed to achieve high yield PEGylation with a stoichiometric equivalence of the reagent. The reagents are easily prepared and precursor forms of our PEG reagents can be used to control the rate of formation of the reactive PEG mono-sulphone in situ that undergoes conjugation with the protein. Purification is often a simple process where un PEGylated protein can be easily recycled to further increase yields. Many classes of therapeutically relevant proteins possess accessible native disulphides. Our studies have shown that peptides, proteins, enzymes and antibody fragments can be site-specifically PEGylated by bis-alkylation using a native, accessible disulphide.


Antibody Fragment Disulphide Bond Certolizumab Pegol Protein PEGylation Reactive Moiety 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Birkhäuser Verlag/Switzerland 2009

Authors and Affiliations

  • Ji-Won Choi
    • 1
  • Antony Godwin
    • 1
  • Sibu Balan
    • 1
  • Penny Bryant
    • 1
  • Yuehua Cong
    • 1
  • Estera Pawlisz
    • 1
  • Manuchehr Porssa
    • 1
  • Norbert Rumpf
    • 1
  • Ruchi Singh
    • 1
  • Keith Powell
    • 1
  • Steve Brocchini
    • 1
    • 2
  1. 1.PolyTherics Ltd.London Bioscience Innovation CentreLondonUK
  2. 2.Department of Pharmaceutics, The School of PharmacyUniversity of LondonLondonUK

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