Figure 4: Typical cyclic voltammogram of PQQ-GDH-(His-tag)/Cu/Au electrode in the presence of 5 mM D(+)-Glucose without treatment involving imidazole solution (dotted-line) and with treatment involving imidazole solution (solid line),in 50 mM HEPES-NaOH buffer (pH 7.5) at a scan rate of 0.01 V/s.