(62z) Enzyme Loading and Activity in Nanoporous Metal Oxides

The activity of the antioxidant enzyme catalase loaded onto the surface or into the pores of silica-based nanoporous materials was studied. Four different types of mesoporous materials were created using published procedures from the Rankin group: amorphous non-porous silica micro particles, nanoporous silica with small radially oriented pores, hollow spherical silica with parallel nanopores (T3), and hollow spherical silica with large, interconnected bimodal nanopores (HSSP-I). The materials were characterized by nitrogen adsorption and dynamic light scattering to confirm that they have characteristics similar to those reported in the literature. Once the materials were synthesized, they were loaded with the enzyme catalase. To test protection of catalase by the silica supports, samples of enzyme-loaded materials were exposed to the proteolytic enzyme pronase and then the temperature was reduce to stop pronase activity. The catalase activity was tested by exposing the either free enzyme or enzyme-loaded materials to peroxide and measuring the rate of degradation using UV-Vis spectrophotometry. Consistent with expectations, the materials with the largest, most accessible pores (HSSP-I) showed the greatest degree of catalase loading and protection from pronase. However, the material with parallel, smaller channels showed some degree of protection from pronase, suggesting either that the pores were partially accessible, or that the enzymes were protected to some degree by adsorbing to the external particle surface.