Immobilization of enzyme on P(GMA-EDGMA) macroporous carriers modified by different amines

Hyperbranched amine (DHA-NH₂) with dendritic structure was designed and synthesized. Infrared spectrum and nuclear magnetic resonance were employed to investigate the structure and property. P(GMA-EDGMA) resins were modified by DHA-NH₂, ethylenediamine, hexamethylenediamine and diethylenetriamine respectively, then four immobilized enzyme carriers of which surfaces has different amino groups were obtained. Papain was chosen as the model of immobilized enzyme to study the structure-activity relationship between amino structures and immobilized enzyme activity. The results indicate that when the amino contents are almost the same, the activity sequence for immobilization of papain is diethylenetriamine>hexamethylenediamine>ethylenediamine> DHA-NH₂. The activity of immobilized enzyme was decided by the number, density of functional groups and length of active segments. Any one of these three factors increases, the immobilized enzyme activity can be improved in a certain content.