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Amperometric DNA sensor using the pyrroquinoline quinone glucose dehydrogenase-avidin conjugate
Kazunori Ikebukuro1, Yumiko Kohiki, Koji Sode
1Department of Biotechnology, Faculty of Technology, Tokyo University of Agriculture and Technology, 2-24-16 Naka-machi, Koganei-shi, Tokyo 184-8588, Japan.
Abstract:
A new amperometric DNA sensor was constructed using a pyrroquinoline quinone glucose dehydrogenase ((PQQ)GDH) conjugated with avidin. Our aim was to specifically detect the DNA sequence of the invA virulence gene from the pathogenic bacterium Salmonella. Probe DNA with a sequence complementary to that of a specific fragment of the invA gene was immobilized onto a carbon paste electrode. After hybridization with biotinylated target DNA, (PQQ)GDH-avidin conjugate was added and the resulting electric current was measured. The electric current is generated from glucose oxidization catalyzed by (PQQ)GDH via 1-methoxyphenazine methosulphate (m-PMS) electron mediator. The sensor response increased with the addition of glucose and in the presence of 6.3 mM glucose the response increased with increasing DNA in the range 5.0x10(-8)-1.0x10(-5) M.