Electrochemical Aldose Detection with PQQ-Dependent Aldose Dehydrogenase

摘要

In this work an enzyme electrode was constructed for amperometric determinationof xylose and glucose. The electrode was based on the pyrroloquinoline quinone (PQQ)-dependent membrane-bound aldose dehydrogenase (AlDH) from Gluconobacter oxydans. PQQ-dependent enzymes are particularly suitable for amperometric detection of analytes, since they are oxygen insensitive and the redox-cofactor PQQ remains tightly bound to the enzyme. The preliminary experiments on amperometric aldose detection with ALDH were performed in a batch system, with ALDH covalently immobilized on a graphite electrode. Another immobilization method used in this study was the absorption of ALDH on carbon paste electrodes. Different flow injection configurations based on ALDH-Modified solid graphite or carbon paste electrodes or on controlled pore glass immobilized ALDH were investigated during this work. The controlled pore glass immobilized ALDH and carbon paste electrodes were successfully used in the measurement of real fermentation samples. Futhermore, samples containing both xylose and glucose could be measured satisfactorily when the measurement with ALDH was combined with separate glucose measurement.