Performance comparison of immobilized enzyme on the titanate nanotube surfaces modified by poly(dopamine) and poly(norepinephrine)

Abstract

Novel hybrid carriers for enzyme immobilization, titanate nanotubes (TNTs) coated by poly(dopamine) (pDA) and poly(norepinephrine) (pNE), have been fabricated by a facile bio-inspired approach under mild conditions in this study. Catalase (CAT) has been immobilized on the TNT surface modified by pDA and pNE as a model enzyme, and their activity and stability have been compared. The immobilization capacities of TNT-pDA and TNT-pNE for CAT are 311.7 and 245.6 mg of g per support, respectively; while their corresponding relative activities are 52% and 56% of native CAT, respectively. It is found that the surface roughness play an important role for the performance difference of immobilized CAT. With the increase of surface roughness, the enzyme loading increases; however, the ratio of active proteins to adsorbed total proteins decreases, witnessing a reduction in the accessibility of enzyme active sites.