earticle

영어

A sorbitol dehydrogenase (GoSLDH) from Gluconobacter oxydans G624 (G. oxydans G624) was codon optimesed and expressed in Escherichia coli BL21(DE3)-CodonPlus RIL. Among various polyols, GoSLDH exhibited highest activity towards D-sorbitol with Km and kcat values of 38.9 mM and 3820 S-1, respectively. The enzyme showed strong preference for NADP+ (only 2.5% relative activity with NAD+). Sequence and structure analysis of GoSLDH along with the biochemical properties confirmed that GoSLDH belongs to the family of NADP+ dependent polyol specific long-chain sorbitol dehydrogenase. Isothermal titration calorimetry showed that the protein binds strongly to D-sorbitol compared with other L-sorbose producing enzymes and substrate docking analysis confirmed the higher turnover rate. High oxidation potential of GoSLDH for D-sorbitol was confirmed by cyclovoltametric analysis. Further, stability of the GoSLDH was significantly improved up to 6-folds after immobilization on the silica nanoparticles and retained 62.8% residual activity after 10 cycles of reuse. Therefore, the immobilized GoSLDH should be useful for industrial production of L-sorbose from D-sorbitol.