Tetrose

A tetrose is a monosaccharide with 4 carbon atoms. '' They either have an aldehyde functional group in position 1 (aldotetroses) or a ketone functional group in position 2 (ketotetroses).

The aldotetroses have two chiralatrial centres ("asymmetric carbon atoms") and so 4 different stereoisomers are possible.

The naturally occurring aldotetroses are:


 * D -Erythrose
 * D -Threose

The 2 D -aldotetroses are:

CH=O       CH=O |          |     HC-OH     HO-CH |          |     HC-OH       HC-OH |          |      CH2OH       CH2OH D -Erythrose   D -Threose

The ketotetroses have 1 chiral centres and therefore 2 possible stereoisomers &mdash; Erythrulose ( L - and D -form).

The D -ketotetrose is:

CH2OH |         C=O |        HC-OH |         CH2OH D -Erythrulose

The only naturally occurring ketotetrose is D -erythrulose.