Polyethylene glycol (PEG) is a family of long chain polymers attached to a glycerine backbone. It is a non-toxic, uncharged, biocompatible, strongly hydrophilic polymer, which has a large exclusion volume in aqueous solution (1). The covalent attachment of PEG (PEGylation) is commonly used to modify a variety of proteins and drugs (2 - 4).
Due to the uncharged and biocompatible nature of PEG it is not very immunogenic and thus very difficult to raise antibodies against. After extensive development, we have successfully generated multiple high quality PEG RabMAb primary antibodies.
The modification of a biopharmaceutical with PEG increases its hydrodynamic radius, and reduces immunogenicity and proteolytic cleavage. Other benefits include decelerated renal excretion, improved stability towards proteolysis and increased solubility of the biopharmaceutical in aqueous solutions.
An anti-PEG antibody can be used to monitor a drug's pharmacokinetics, including distribution, metabolism and excretion. Also, it can be used for the quality control of PEGylated molecules in ELISA, WB and IHC.
The PEG RabMAb ELISA kit (ab215546) operates on the basis of competition between the enzyme (HRP) conjugated PEG and PEG labeled molecules for a limited number of binding sites on the surface of 96-wells coated with Anti-PEG rabbit monoclonal antibody. The extent of color development resulted from interaction between HRP and substrate TMB is inversely proportional to the amount of PEGylated molecules in the sample (Fig 1).
Fig 1. Competition between PEG labeled HRP (H) and PEG labeled sample (S) in PEG RabMAb ELISA assay.
2. Wong, S.S. (1991), Reactive groups of proteins and their modifying agents. In Chemistry of Protein conjugation and cross-linking, p. 13, CRC Press.