Reference Work Entry

Encyclopedia of Astrobiology

pp 680-681



Glyceraldehyde is one of the simplest sugars; its chemical structure is CH2OH–CH2OH–CHO. It is classified as a triose (sugar with three carbons), and as an aldose (sugar with an aldehyde group). Since the middle carbon atom is connected to four different groups (H, OH, CHO, and CH2OH), it has enantiomers: d-glyceraldehyde and l-glyceraldehyde. Terrestrial organisms largely use only d-glyceraldehde and other d-sugars. d-Glyceraldehyde (as its phosphate ester) plays important roles in sugar metabolism such as in the Benson–Calvin cycle of photosynthesis and in glycolysis. It can be synthesized by mild oxidation of glycerol. It is formed in the formose reaction, i.e., the polymerization of formaldehyde with a catalyst in basic aqueous solution. It has not been detected in carbonaceous chondrites nor in interstellar space, although the other triose, dihydroxyacetone, has been reported in both (these interstellar identifications have more recently been questioned).

This is an excerpt from the content