Synthesis of carboxylated poly(NIPAAm) oligomers and their application to form thermo-reversible polymer-enzyme conjugates

Abstract

A thermo-reversible poly(N-isopropylacrylamide) poly(NIPAAm) oligomer with a carboxyl functional end group has been synthesized by radical polymerization using β-mercaptopropionic acid as a chain transfer reagent. This polymer has been conjugated to an enzyme, β-D-glucosidase, to form a thermo-reversible water soluble-insoluble polymer-enzyme conjugate. This conjugate can be used for separation, recovery and recycle of an enzyme simply by applying small temperature changes to the reaction medium. In contrast to the random polymer-enzyme conjugates reported in the literature, in this study the enzyme is coupled to each polymer chain by a single end attachment. These preliminary studies show that the conjugated enzyme exhibits very high retention of activity ( > 90%) compared to the native enzyme and shows improved thermal stability.

Keywords:

• Poly(isopropylacrylamide) oligomer
• chain transfer polymerization
• β-D-glucosidase
• thermo-reversible polymer-enzyme conjugate
• soluble-insoluble polymer-enzyme conjugate