Syntheses and applications of water‐soluble reactive polymers for purification and immobilization of biomolecules

Reactive polymers have been prepared by copolymeriz‐ing N‐isopropyl acrylamide (NIPAM) with N‐acryloxy‐succinimide (NASI) or glycidyl methacrylate (GMA). The amino groups of ligands could react with the residues of NASI or GMA and the polymers could be precipitated by temperature and/or salinity variation, since they contained the NIPAM residues. As a model, p‐aminobenza‐midine, a trypsin inhibitor, was attached to the polymers to form water‐soluble macroligands, capable of selectively binding trypsin from a trypsin–chymotrypsin solution. After precipitation of the macroligand–trypsin complex, followed by dissociation, approximately 82% trypsin was isolated. The NIPAM‐GMA copolymer was also reacted with immunogammaglobulin (IgG) and alkaline phosphatase (AP). It was demonstrated that the IgG bearing polymer was able to bind protein A and the whole complex was precipitable. The reactive polymer was also used for direct immobilization of AP which was active in repeated reactions.