Arabinose is an
aldopentose
In chemistry, a pentose is a monosaccharide (simple sugar) with five carbon atoms. The chemical formula of many pentoses is , and their molecular weight is 150.13 g/mol.[monosaccharide
Monosaccharides (from Greek ''monos'': single, '' sacchar'': sugar), also called simple sugars, are the simplest forms of sugar and the most basic units (monomers) from which all carbohydrates are built.
They are usually colorless, water-solub ...]
containing five
carbon
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent
In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with o ...
atom
Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons.
Every solid, liquid, gas, and ...
s, and including an
aldehyde
In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl grou ...
(CHO)
functional group
In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the rest ...
.
For biosynthetic reasons, most saccharides are almost always more abundant in nature as the "
D"-form, or structurally analogous to
D-glyceraldehyde.
[The D/L nomenclature does not refer to the molecule's optical rotation properties but to its structural analogy to ]glyceraldehyde
Glyceraldehyde (glyceral) is a triose monosaccharide with chemical formula C3 H6 O3. It is the simplest of all common aldoses. It is a sweet, colorless, crystalline solid that is an intermediate compound in carbohydrate metabolism. The word comes ...
. 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
A hemicellulose (also known as polyose) is one of a number of heteropolymers (matrix polysaccharides), such as arabinoxylans, present along with cellulose in almost all terrestrial plant cell walls.Scheller HV, Ulvskov Hemicelluloses.// Annu Rev ...
and
pectin
Pectin ( grc, πηκτικός ': "congealed" and "curdled") is a heteropolysaccharide, a structural acid contained in the primary lamella, in the middle lamella, and in the cell walls of terrestrial plants. The principal, chemical component of ...
.
The
L-arabinose operon, also known as the araBAD operon, has been the subject of much biomolecular research. The
operon
In genetics, an operon is a functioning unit of DNA containing a cluster of genes under the control of a single promoter. The genes are transcribed together into an mRNA strand and either translated together in the cytoplasm, or undergo splic ...
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.
:
Etymology
Arabinose gets its name from
gum arabic
Gum arabic, also known as gum sudani, acacia gum, Arabic gum, gum acacia, acacia, Senegal gum, Indian gum, and by other names, is a natural gum originally consisting of the hardened sap of two species of the ''Acacia'' tree, '' Senegalia se ...
, from which it was first isolated.
Merriam Webster Dictionary
/ref>
Use in foods
Originally commercialized as a sweetener, arabinose is an inhibitor of sucrase, the enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
that breaks down sucrose
Sucrose, a disaccharide, is a sugar composed of glucose and fructose subunits. It is produced naturally in plants and is the main constituent of white sugar. It has the molecular formula .
For human consumption, sucrose is extracted and refined ...
into glucose
Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using ...
and fructose
Fructose, or fruit sugar, is a Ketose, ketonic monosaccharide, simple sugar found in many plants, where it is often bonded to glucose to form the disaccharide sucrose. It is one of the three dietary monosaccharides, along with glucose and galacto ...
in the small intestine
The small intestine or small bowel is an organ in the gastrointestinal tract where most of the absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the p ...
.
See also
* Arabinosyl nucleosides
Arabinosyl nucleosides are derivatives of the nucleosides. They contain – in contrast to most nucleosides – instead of the β-D-Ribofuranose the β-D-Arabinofuranose. They are mostly used as cytostatics or virostatics.
Examples
File:Cyta ...
Notes
References
{{carbohydrates
Aldopentoses
Glycerols