What is "arabinose"

Pentose \Pen"tose\, n. [Penta- + -ose.] (Chem.) Any of a group of sugars of the formula C5H10O5, such as as arabinose or ribose; -- so called from the five carbon atoms in the molecule. They are not fermented by yeast.

n. (context carbohydrate English) An aldopentose that occurs most often in polysaccharides such as hemicellulose and pectin.

Arabinose is an aldopentose – a monosaccharide containing five carbon atoms, and including an aldehyde (CHO) functional group.

For biosynthetic reasons, most saccharides are almost always more abundant in nature as the "D"-form, or structurally analogous to D-glyceraldehyde. However, L-arabinose is in fact more common than D-arabinose in nature and is found in nature as a component of biopolymers such as hemicellulose and pectin.

The L-arabinose operon, also known as the araBAD operon, has been the subject of much biomolecular research. The operon directs the catabolism of arabinose in E. coli, and it is dynamically activated in the presence of arabinose and the absence of glucose.

A classic method for the organic synthesis of arabinose from glucose is the Wohl degradation.

:{| class="wikitable" |- style="background-color:#FFDEAD;" ! colspan="2" | D-Arabinose |- | align="center" |
α-D-Arabinofuranose | align="center" |
β-D-Arabinofuranose |- | align="center" |
α-D-Arabinopyranose | align="center" |
β-D-Arabinopyranose |}