Investigation of bioelectrocatalytic systems with PQQ-dependent GDH and carbonaceous materials

Abstract

Different graphite oxidation techniques have been applied aiming to synthesize five different graphene oxides (GOs). Carbonaceous material electrodes (CMEs) were prepared using GOs, amorphous carbon and graphite. Bioelectrocatalytic systems were constructed by formation of pyrroloquinoline quinone (PQQ) dependent glucosedehydrogenase (PQQ-GDH) isolated from Acinetobacter calcoaceticus layers on the CMEs. The fact of direct electron transfer (DET) from the active site of PQQ-GDH to the CMEs has been studied. The proposed bioelectrocatalytic systems have been characterized by kinetic parameters – the apparent Michaelis constant (KMapp) and the apparent maximum current (Imaxapp). It has been concluded that a definite set of the surface functional groups as well as the nano-scale carbon structures are essential for obtained reagentless enzyme-based biosensors. Data of the atomic force microscopy (AFM) analysis revealed the DET efficiency to depend on the content of functional groups in the GOs as well as on its surface morphology. Keywords: carbonaceous materials, PQQ-dependent GDH, bioelectrocatalysis, direct electron transfer