Purified recombinant sorbose dehydrogenase from Sinorhizobium sp. 97507 exhibited high reactivity for 1,5-anhydro-d-glucitol (1,5-AG) and l-sorbose, but little activity for the other sugars or sugar alcohols tested. Kinetic analysis revealed that its catalytic efficiency (kcat/Km) for l-sorbose and 1,5-AG is 1.8 × 102 and 1.5 × 102 s−1·M−1, respectively.