Purification and Properties of Membrane-bound D -Sorbitol Dehydrogenase fromGluconobacter suboxydansIFO 3255

D-Sorbitol dehydrogenase was solubilized from the membrane fraction of Gluconobacter suboxydans IFO 3255 with Triton X-100 in the presence of D-sorbitol. Purification of the enzyme was done by fractionation with column chromatographies of DEAE-Cellulose, DEAE-Sepharose, hydroxylapatite, and Sephacryl HR300 in the presence of Triton X-100. The molecular mass of the enzyme was 800 kDa, consisting of homologous subunits of 80 kDa. The optimum pH of the enzyme activity was 6.0, and the optimum temperature was 30 degrees C. Western blot analysis suggested the occurrence of the enzyme in all the Gluconobacter strains tested.