L-Iditol 2-dehydrogenases

Enzymes classified as EC 1.1.1.14 that reversibly interconvert the sugar alcohols L-iditol and L-sorbose, and also act on D-glucitol to produce D-fructose. Biochemists know them best as sorbitol dehydrogenases, key players in the polyol pathway by which cells convert glucose to fructose, a route implicated in diabetic complications when it runs excessively in tissues such as the lens and nerves. In food analysis they provide a specific enzymatic method for measuring sorbitol in sugar-free products, juices, and diabetic foods, offering a faster alternative to chromatography. Their ability to distinguish closely related sugar alcohols makes them useful research tools for carbohydrate chemistry as well. Like many dehydrogenases, they depend on the cofactor NAD for their catalytic activity.