Synthesis of Thermal Phase Separating Reactive Polymers and Their Applications in Immobilized Enzymes

This paper describes the synthesis of active ester copolymers from N-isopropylacrylamide (NIP) with N-acryloxysuccinimide (NAS), aminolysis of active esters, and determination of their average molecular weights. As a model, thermolysin was attached to the polymer to form soluble-insoluble immobilized enzymes capable of being centrifuged above their Tc, because poly(N-isopropylacylamide) (poly(NIP)) has a lower critical solution temperature (Tc) of about 31–33°C. The effects of immobilization of enzymes have been studied including the amount of active ester, time, pH, temperature, and ratio of polymer to enzyme. The tests of thermal stability and repeated precipitation and separation showed that the use of Tc as the technique of separation is possible.