| abstract |
The invention relates to the development of in vitro assay systems that force the release of a water-soluble polymer, such as polyethylene glycol (PEG) and polysialic acid (PSA), from proteins modified with a reversibly-linked water-soluble polymer. The invention includes methods for analyzing the release of the water- soluble polymer and measuring regained protein activity. The invention further includes methods appropriate for the quality control of proteins modified with releasable water-soluble polymers, including polymers like PEG and PSA. |