Allose

Allose is a rare aldohexose sugar. It is a monosaccharide, meaning it is the simplest form of carbohydrate. Allose is an epimer of glucose, differing from it only in the configuration at the carbon atom 3. In aqueous solution, allose exists in equilibrium between its cyclic hemiacetal forms, allopyranose and allofuranose, and its open-chain aldehyde form, allose. The pyranose form is more stable and predominates. Allose is found naturally in small amounts in some plants, such as in the leaves of the genera Eucalyptus and Melaleuca. It has also been identified in some microorganisms. Allose is not a major component of biological systems and is not considered a metabolically important sugar in humans. Its presence in biological tissues is generally limited. Research into its biological functions is ongoing, but it is not a widely studied sugar compared to more common hexoses like glucose or fructose. Allose can be synthesized in the laboratory and has been used in biochemical research.