Development of Highly-sensitive Fructosyl-valine Enzyme Sensor Employing Recombinant Fructosyl Amine Oxidase

Abstract

We recently isolated a novel fructosyl-amine oxidase (FAOD) from the soil bacterium Arthrobacter sp. FV 1-1, cloned the gene encoding FAOD and succeeded in the recombinant production. This bacterial FAOD showed high specificity towards fructosyl valine (FV), a proteolytic product of hemoglobin A1c (HbA1c), but was almost completely inactive towards ε-fructosyl-lysine (ε-FK), a proteolytic product of glycated albumin. By utilizing recombinant FAOD expressed in E. coli, an FAOD sensor based on hydrogen peroxide detection was constructed. The sensor showed FV specificity, with a minimum detectable concentration of 1 μM. The sensitivity was 7.1 mAM^-1cm^-2, which is 17 times higher than that of the previously reported FAOD-based enzyme sensors. Because the bacterial FAOD-based sensor could detect FV concentration and discriminate FV in the presence of ε-FK, it has the great potential for use in the measurement of HbA1c in whole blood samples.