▎ 摘　　要

Herein, a rapid and highly sensitive amperometric biosensor for the detection of alpha-ketoglutarate (alpha-KG) was constructed via an electrochemical approach, in which the glutamate dehydrogenase (GLUD) was modified on the surface of reduced graphene oxide-gold nanoparticle composite (rGO-Au(nano)composite). The rGO-Au(nano)composite was one-step electrodeposited onto glassy carbon electrode (GCE) surface and was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and electrochemical techniques. In addition, the rGO-Au-nano/GCE was also found to electrocatalyze the oxidation of beta-nicotinamide adenine dinucleotide (NADH) at the peak potential of 0.3 V, which was negatively shifted compared with that at bare GCE or Au-nano/GCE, illustrating better catalytic performance of rGO-Au-nano. After the modification of GLUD, the GLUD/rGO-Au-nano/GCE led to effective amperometric detection of alpha-KG through monitoring the NADH consumption and displayed a linear response in the range of 66.7 and 494.5 mu M, with the detection limit of 9.2 mu M. Moreover, the prepared GLUD/rGO-Au-nano/GCE was further evaluated to be highly selective and used to test alpha-KG in human serum samples. The recovery and the RSD values were calculated in the range of 97.9-102.4% and 3.8-4.5%, respectively, showing a great prospect for its real application.