Sensitive measurement of polyethylene glycol-modified proteins

Abstract

An IgM monoclonal antibody (AGP3) against polyethylene glycol (PEG) was used to assay PEG-modified proteins by ELISA. PEG-modified β-glucuronidase could be measured at concentrations as low as 15 ng/mL, corresponding to 750 pg (1.8 fmol) of conjugate. This ELISA should be generally applicable to all PEG-modified proteins because AGP3 binds the backbone of the PEG chain independent of the linker used for PEG attachment.