Basic Research for Development of Biocatalyst-modified Electrodes

点击翻译按钮获取中文摘要

This study was carried out for aiming at the development of enzyme-modified electrodes functioning as biocatalyst electrodes which are applicable to a wide variety of field such as those in biosensor and bioreactor technologies. Two kinds of enzymes, ie. diaphorase and membrane-bound enzymes were used. Diaphoraso was immobilized on the surface of a carbon paste electrode by the method developed by the authos. The electrode functioned as an exellent NADH sensor. A combination of the diaphorase reaction with a dehydrogenase reaction allowed for the detection of NADH and NAD as low as picomolar order, based on a cycling effect. A quantitative method has been establised for evaluating the capability of a variety of redox compounds for electron transfer mediation between the enzyme and the electrode. A quinoprotein and flavoprotein, both of which contain heme C in their molecules, were examined as candidates suitable for immobilizing on the surface of electrodes of a variety of materials. They were found to be adsorbed on these electrode surface keeping with their enzyme activity and allowing the direct electron transfer at the electrodes. Thus we have found a suitable system for constructiang the biocat alyst electrode. Some applications of this type of electrode were also studied ; for example, a possibility for microtype fructose sensor based on the direct electron transfer between a carbon paste electrode and fructose dehydrogenase adsorbed on it was suggested based on the present study.