Biotechnology Letters, Vol.16, No.5, 455-460, 1994
Glu742 Substitution to Lys Enhances the EDTA Tolerance of Escherichia-Coli PQQ Glucose-Dehydrogenase
Based on homology analysis of the PQQ (pyrroloquinoline quinone) glucose dehydrogenase (PQQGDH) gene from Esherichia coli and Acinetobacter calcoaceticus, Glu742 was substituted to Lys by site directed mutagenesis of the E. coli PQQGDH gene (gcd). The mutant enzyme, E742K showed higher tolerance towards EDTA inactivation than wild type PQQGDH. This is the first mutagenesis study of putative a PQQ binding site in PQQ enzyme.