RESUMO
Purified recombinant sorbose dehydrogenase from Sinorhizobium sp. 97507 exhibited high reactivity for 1,5-anhydro-D-glucitol (1,5-AG) and L-sorbose, but little activity for the other sugars or sugar alcohols tested. Kinetic analysis revealed that its catalytic efficiency (k(cat)/Km) for L-sorbose and 1,5-AG is 1.8 × 10(2) and 1.5 × 10(2) s(-1)·M(-1), respectively.
Assuntos
Desidrogenases de Carboidrato/metabolismo , Desoxiglucose/metabolismo , Sinorhizobium/enzimologia , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Desidrogenases de Carboidrato/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Sinorhizobium/genética , Sorbose/metabolismo , Especificidade por SubstratoRESUMO
A novel FAD-dependent glucose dehydrogenase (FAD-GDH) was found and its enzymatic property for glucose sensing was characterized. FAD-GDH oxidized glucose in the presence of some artificial electron acceptors, except for O2, and exhibited thermostability, high substrate specificity and a large Michaelis constant for glucose. FAD-GDH was applied to an amperometric glucose sensor with Fe(CN)6(3-) as a soluble mediator. The use of a relatively high concentration of Fe(CN)6(3-) resulted in a good linearity between the current response and the glucose concentration, taking into account a large Michaelis constant for Fe(CN)6(3-). The glucose sensor was completely insensitive to O2 and responded linearly to glucose up to 30 mM. Compared to glucose, the response to other saccharides was negligible. The sensor can be stored at room temperature in a desiccator for at least one month without any change in the response or activity.