Catalase Immobilization on Amino-activated Fe3O4@SiO2 Nanoparticles: Loading Density Affected Activity Recovery of Catalase

Publication date: Available online 27 March 2017 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Liang Wang, Guo Chen, Jun Zhao, Ning Cai A blackberry-shaped Fe3O4@SiO2 nanoparticles were prepared, characterized and applied in covalently binding catalase. The enzyme loading decreased with the increase of pH, however, the activity recovery increased simultaneously. To elucidate the influence factor of the activity recovery, the enzyme loading was further regulated by changing the initial free enzyme content. The relationship between enzyme loading and activity recovery showed the consistent trend, whether the variation of enzyme loading was incurred by pH or by initial enzyme content. The simulated parameters showed the similar values according to the experiment at different conditions. It was concluded that activity recovery was dominated by protein density on surface, not by the orientation of the enzyme on surface, due to the negligible diffusion limit for H2O2 as the substrate of catalase. The immobilized catalase at pH 7.0 has a high activity recovery of 100% at 14.4 enzyme μg/mg nanoparticles. The Km and Vmax of the immobilized enzyme above are 0.215mol and 0.797mol/min, similar to 0.167mol and 0.727mol/min for the free enzyme, respectively. Graphical abstract
Source: Journal of Molecular Catalysis B: Enzymatic - Category: Biochemistry Source Type: research