Sol-gel immobilized glucose-oxidase: Calorimetric investigations of enzyme activities

Using the sol-gel process, the enzyme glucose-oxidase was immobilized in modified SiO2 layers. The tetraethoxysilane based sol was varied by veratrylaldehyde, aminopropyltriethoxysilane and an azomethine compound, which was synthesized from both molecules. Changes in reaction kinetics of the sol-gel process by addition of veratrylaldehyde were observed by Si-29 NMR measurements. The fixation of this additive in the final gel was clarified by FTIR spectroscopy. The influence of inserted functional groups on the enzyme activity was determined by calorimetry. The Enzyme Thermistor is a fast and uncomplicated method to obtain comparative results of sol-gel immobilized enzyme activity. Differences in immobilization effects were found dependent on structure and concentration of additives.