Dfructose

D-fructose is the dextrorotatory enantiomer of fructose, a monosaccharide in the ketose family with the formula C6H12O6. It is one of the two enantiomers of fructose, the other being L-fructose, which is the mirror image. In nature, D-fructose is the form most commonly found in fruits, honey, and many commercial sweeteners.

As a ketohexose, D-fructose shares the same molecular formula as glucose but differs in structural arrangement and stereochemistry. In solution, it can adopt multiple cyclic forms, including furanose and pyranose rings, and undergo mutarotation between these anomeric forms. In solution, D-fructose is typically found in several hydrated ring forms, with the open-chain form in equilibrium with the cyclic forms.

Metabolically, D-fructose is absorbed in the gut and transported to the liver, where it is phosphorylated by fructokinase to fructose-1-phosphate. Aldolase B cleaves this intermediate into glyceraldehyde and dihydroxyacetone phosphate (DHAP). Glyceraldehyde is then converted to glyceraldehyde-3-phosphate; DHAP can enter glycolysis or gluconeogenesis. This pathway bypasses the main regulatory step of glycolysis (phosphofructokinase-1), so excessive fructose intake can promote de novo lipogenesis and has been linked in observational studies to metabolic health concerns, though the relationship depends on total dietary patterns.

D-fructose is distinct from D-glucose, another hexose, in both structure and metabolic fate. It is widely used in the food industry and occurs naturally in many fruit-derived products.