Enzyme-modified electrodes are core components of bioelectronic devices, such as biosensors and biofuel cells, generating electricity from medical analytes and natural fuel molecules. Most of these devices employ the mediated electron transfer between enzyme active sites and electrode surface via a redox-active molecules called mediators. Conventional mediator molecules are water soluble and freely diffuse into the active site at deep inside of enzyme shell.However, enzymatic fuel cells with diffusing mediators require unwanted complexity component to avoid the cross-talk between anode/cathode systems. In addition, the continuous glucose monitoring (CGM) has begun to be considered for diabetes management. In a CGM sensor, it is necessary that the mediator does not enter the body after detaching from the sensor. These recent backgrounds have made the co-immobilization of enzyme and mediator more important. In this study, we present here a novel enzyme electrode system using glucose dehydrogenase (GDH) and N,N’-diphenyl-p-phenylenediamine (DPPD) as a mediator molecule that can shuttle electrons between the electrode and the reaction center of GDH modified on the electrodes.The DPPD-adsorbed carbon nanotube modified carbon fabric (CNT/CF) electrode or glassy carbon (GC) electrode were modified by GDHs crosslinked with glutaraldehyde to prepare a GDH-DPPD/CNT/CF electrode or GDH-DPPD/GC electrode. CNT/CF electrode was fabricated according to the method described in the previous study [1].The performance of GDH-DPPD/CNT/CF electrode was evaluated. The catalytic current appeared from the oxidation potential of DPPD (0.1 V vs. Ag/AgCl) and reached the mA cm-2 order at 0.4 V. Importantly, the catalytic current of GDH-DPPD/GC electrode was maintained at 99% after four replacements of the glucose solution. We proposed the novel mechanism of DPPD-madiated GDH reaction as illustrated in the figure. The oxidized form of DPPD detaches from the carbon electrode and transfers to GDH (i), and reduced with FAD of GDH in the presence of glucose (ii). The reduced DPPD returns to the carbon electrode and is re-oxidized (iii, iv). These reactions (i)-(iv) are repeated for DPPD shuttling-based mediation of the continuous glucose oxidation with GDH-modified electrodes. The several evidences supporting this mechanism will be reported in the presentation.[1] K. Haneda, et al. Electrochimica Acta., 82, 175-178 (2003). Figure 1