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.