PolyTherics has developed TheraPEG technology, a novel and cost-effecitve approach to PEGylation that exploits the selective chemistry of naturally occurring disulfide bonds in proteins for the attachment of PEG in targeted, site-specific fashion.
PolyTherics has shown that disulfide bonds can be made more stable through the addition of a chemical bridge which does not compromise the tertiary structure of the protein. This property has made it possible to exploit the conjugating thiol selectivity of the two sulfurs comprising a disulfide bond and create a bridge for the site-specific attachment of PEG.
Since disulfide bonds occur naturally in the structure of most proteins, TheraPEG technology avoids any artificial engineering to introduce cysteine residues for PEG attachment.
The process by which the chemical bridge is attached is equilibrium-driven and in contrast to other PEGylation methods, distinct, in that none of the reagents used undergo competitive reaction with either amine groups or water. This enables the entire TheraPEG process to be more readily controlled. Furthermore, the bridging moiety imposes no limitation on the size of PEG molecule that can be accommondated within the protein structure; PEG up to 30 kDa in molecular weight, in either linear or branched form, has been successfully validated using the PolyTherics approach.