Magnetic nanoparticles in biocatalysis

Abstract

The properties of enzymatic systems based on horseradish root peroxidase immobilized on magnetic particles were studied. Magnetic Fe3O4 nanoparticles were synthesized by co-precipitation. Then, horseradish root peroxidase was immobilized on their surface in two ways by covalent crosslinking. For this purposes, in the first case, Fe3O4 was sequentially treated with tetraethoxysilane, 3-minopropyltriethoxysilane, glutaraldehyde and HRP. In the second case, before immobilization of HRP, 3-minopropyltriethoxysilane, glutaraldehyde and HRP were sequentially deposited onto the support surface. The activity of the synthesized biocatalysts was evaluated spectrophotometrically in the oxidation reaction of 2,2’-azino-bis (3-ethylbenzothiazolin-6-sulfonate) ammonium with hydrogen peroxide. The kinetic parameters K m and V max were also calculated for all types of catalysts, including native HRP. Among all biocatalytic systems, the best values, compared with the native enzyme (K m = 4 mmol/L and V max = 12.6 · 10−4, mmol/L·s), were obtained for the first type of biocatalyst (K m = 5 mmol / L and V max = 2.5 · 10−4, mmol/L·s). It was also determined that the optimum pH is 7.2.