Aldose



An aldose is a monosaccharide (a simple sugar) that contains only one aldehyde (-CH=O) group per molecule. The chemical formula takes the form Cn(H2O)n. The simplest possible aldose is the diose glycolaldehyde, which only contains two carbon atoms.

Because they have at least one asymmetric carbon centre, aldoses exhibit stereoisomerism. This means an aldose can exist in either a D form or L form of a Fischer projection. Biological systems tend to recognise D-aldoses more than L-aldoses.

An aldose differs from a ketose in that it has a carbonyl group at the end of the carbon chain instead of in the middle. This allows ketoses and aldoses to be chemically differentiated through Seliwanoff's test. An aldose may isomerize to a ketose through the Lobry-de Bruyn-van Ekenstein transformation.

List of aldoses

 * Diose: glycolaldehyde
 * Triose: glyceraldehyde
 * Tetroses: erythrose, threose
 * Pentoses: ribose, arabinose, xylose, lyxose
 * Hexoses: allose, altrose, glucose, mannose, gulose, idose, galactose, talose