A potentially insect-implantable trehalose electrooxidizing anode.
The dominant sugar in the body fluids of many insects is not glucose, the sugar of the vertebrates, but trehalose. In a step toward a cell that would operate in insects, we describe here a trehalose electrooxidizing anode. The novel component of the anode is its engineered, trehalose oxidation catalyzing, FAD-glucose-3-dehydrogenase (G3DH). Screening for gene-sources of G3DH pointed to the G3DH of Agrobacterium tumefaciens. Sequencing of the A. tumefaciens genome revealed a 1.7 kb fragment which contained the G3DH coding gene. The fragment was isolated, cloned and expressed in E. coli strain BL-21, to yield the approximately 65 kDa his-tagged flavoenzyme, with a specific activity of approximately 2.5U/mg protein. Electrical wiring of its reaction center to a carbon electrode through a high apparent electron diffusion coefficient (5.8 x 10(-6)cm(2)/s) redox hydrogel with a -0.2V versus Ag/AgCl redox potential resulted in the trehalose electrooxidizing anode. Trehalose was electrooxidized at pH 7.2 already at -0.36 V versus Ag/AgCl. At 0 V versus Ag/AgCl the trehalose electrooxidation current density was 0.1 mA/cm(2).
Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712, USA.
Arti
A
Pothukuchy
Nicolas
N
Mano
George
G
Georgiou
Adam
A
Heller
D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D004567:Electrodes, Implanted; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D005948:Glucose Dehydrogenases / Q000737:chemistry*; D007313:Insecta / Q000378:metabolism*; D008839:Microelectrodes; D010084:Oxidation-Reduction; D014199:Trehalose / Q000032:analysis*
D004800:Enzymes, Immobilized; D014199:Trehalose; D005948:Glucose Dehydrogenases