Fig. 2

Expression and catalytic activity of GDH from B. licheniformis WX-02 (WX-02 GDH). a SDS-PAGE of the expression and purification of WX-02 GDH. The recombinant E. coli BL21(DE3)/pET-gdh was grown to the appropriate density and induced with IPTG for the production of the GDH protein. The total-cell extracts from the induced cells were separated into soluble and insoluble fractions. Proteins in the soluble fractions were purified by the Ni–NTA purification kits, and the GDH protein was purified. Lane 1 sediment of cell extracts; lane 2 supernatant of cell extracts; lane 3 purified GDH protein in 50-fold dilution; lane 4 purified GDH protein in tenfold dilution; lane 5 purified GDH protein. b Activities of purified WX-02 GDH on different substrates with corresponding coenzymes