Construction of multi-chimeric pyrroloquinoline quinone glucose dehydrogenase with improved enzymatic properties and application in glucose monitoring

A multi-chimeric enzyme was constructed by combining the protein regions responsible for the enzymatic properties of Escherichia coli and Acinetobacter calcoaceticus pyrroloquinoline quinone glucose dehydrogenase (PQQGDH). The constructed multi-chimeric PQQGDH showed increased co-factor binding stability, thermal stability, an alteration in substrate specificity and a 10-fold increase in the K _m value for glucose compared with the wild-type E. coli PQQGDH. The cumulative effect of each introduced protein region on the improvement of enzymatic properties was observed. The application of the multi-chimeric PQQGDH in amperometric glucose sensor construction achieved an expanded dynamic range together with increased operational stability and narrower substrate specificity. The glucose sensor can measure glucose from 5 to 40 mM, suggesting its potential for the direct measurement of high blood-glucose levels in diabetic patients.