Synthesis and characterization of a soluble, temperature-sensitive polymer-conjugated enzyme

The enzyme, alkaline phosphatase, has been conjugated to a temperature-sensitive polymer which exhibits a lower critical solution temperature (LCST). A series of copolymers containing different molar ratios of N-isopropylacrylamide(NIPAAm) and N-acryloxysuccinimide(NAS) were synthesized and then conjugated to the enzyme. These polymer-enzyme conjugates precipitate and flocculate in aqueous solution above the LCST, and redissolve when cooled below that temperature. The kinetics of the conjugated enzymes have been characterized as a function of temperature and compared to free enzyme. The effect of the conjugation degree between polymer and enzyme on the activity of the conjugated enzymes was also investigated.