Deoxyribose
61388
220011167
2008-06-17T21:31:20Z
128.8.92.31
/* Biological importance of deoxyribose */
{{Chembox new
|Reference=<ref>''Merck Index'', 11th Edition, '''2890'''.</ref>
|ImageFile=Deoxyribose.svg
|ImageSize=180px
|IUPACName=(''2R,4S,5R'')-5-(Hydroxymethyl)tetrahydrofuran-2,4-diol
|OtherNames=D-Deoxyribose<br>2-Deoxy-D-ribose<br>Thyminose
|Section1= {{Chembox Identifiers
| CASNo=533-67-5
| PubChem=439576
| SMILES=C1C(C(OC1O)CO)O
}}
|Section2= {{Chembox Properties
| Formula=C<sub>5</sub>H<sub>10</sub>O<sub>4</sub>
| MolarMass=134.13
| Appearance=White solid
| Density=
| MeltingPtC=91
| BoilingPt=
| Solubility=Very soluble
}}
|Section3= {{Chembox Hazards
| MainHazards=
| FlashPt=
| Autoignition=
}}
}}
[[Image:Deoxyribose1.PNG|thumb|right|400px|Chemical equilibrium]]
'''Deoxyribose''', also known as '''<small>D</small>-Deoxyribose''' and '''2-deoxyribose''', is an [[aldopentose]] — a [[monosaccharide]] containing five [[carbon]] [[atom]]s, and including an [[aldehyde]] [[functional group]] in its linear structure. It is a [[deoxy sugar]] derived from the [[pentose]] [[sugar]] [[ribose]] by the replacement of the [[hydroxyl group]] at the 2 position with [[hydrogen]], leading to the net loss of an [[oxygen]] atom. Replacement of the hydroxyl group also shifts the conformation of the ring from C3'-endo to C2'-endo. It has a [[chemical formula]] of {{carbon}}<sub>5</sub>{{hydrogen}}<sub>10</sub>{{oxygen}}<sub>4</sub>; it was discovered in [[1929]] by [[Phoebus Levene]].
[[Ribose]] forms a five-member ring composed of four carbon atoms and one oxygen. [[Hydroxyl]] groups are attached to three of the carbons. The other carbon and a hydroxyl group are attached to one of the carbon atoms adjacent to the oxygen. In deoxyribose, the carbon furthest from the attached carbon is stripped of the oxygen atom in what would be a [[hydroxyl group]] in ribose. Due to the common C3' and C4' [[stereochemistry]] of D-ribose and D-arabinose, D-2-deoxyribose is also D-2-deoxyarabinose.
'''Deoxyribofuranose''' is an alternative name for the ring structure of deoxyribose. This alternative name merely refers to the fact that deoxyribose has a five membered ring consisting of four carbons and an oxygen and is more a structural description than a name.
== Biological importance of deoxyribose ==
Ribose and 2-deoxyribose derivatives have an important role in biology. Among the most important derivatives are those with phosphate groups attached at the 5 position. Mono-, di-, and triphosphate forms are important, as well as 3-5 cyclic monophosphates. There are also important diphosphate dimers called coenzymes that [[purine]]s and [[pyrimidine]]s form an important class of compounds with ribose and deoxyribose. When these purine and pyrimidine derivatives are coupled to a ribose sugar, they are called [[nucleosides]]. In these compounds, the convention is to put a ′ (pronounced "prime") after the carbon numbers of the sugar, so that in nucleoside derivatives a name might include, for instance, the term "5′-monophosphate", meaning that the phosphate group is attached to the fifth carbon of the sugar, and not to the base. The bases are attached to the 1′ ribose carbon in the common nucleosides. Phosphorylated nucleosides are called [[nucleotide]]s.
One of the common bases is [[adenine]] (a purine derivative); coupled to ribose it is called [[adenosine]]; coupled to deoxyribose it is called [[deoxyadenosine]]. The 5′-triphosphate derivative of adenosine, commonly called [[Adenosine triphosphate|ATP]], for '''a'''denosine '''t'''ri'''p'''hosphate, is an important energy transport molecule in cells.
See ''[[Nucleic acid nomenclature]]'' for a diagram showing the numbered positions in a 5′-monophosphate nucleotide.
2-Deoxyribose and ribose nucleotides are often found in unbranched 5′-3′ [[polymers]]. In these structures, the 3′carbon of one [[monomer]] unit is linked to a phosphate that is attached to the 5′carbon of the next unit, and so on. These polymer chains often contain many millions of monomer units. Since long polymers have physical properties distinctly different from those of small molecules, they are called [[macromolecules]]. The sugar-phosphate-sugar chain is called the backbone of the polymer. One end of the backbone has a free 5′phosphate, and the other end has a free 3′OH group. The backbone structure is independent of which particular bases are attached to the individual sugars.
Genetic material in earthly life often contains poly 5′-3′, 2′-deoxyribose nucleotides, in structures called [[chromosomes]], where each monomer is one of the nucleotides deoxy- [[adenine]], [[thymine]], [[guanine]] or [[cytosine]]. This material is commonly called [[DNA|deoxyribonucleic acid]], or simply [[DNA]] for short.
DNA in chromosomes forms very long helical structures containing two molecules with the backbones running in opposite directions on the outside of the helix and held together by hydrogen bonds between complementary nucleotide bases lying between the helical backbones. The lack of the 2′ hydroxyl group in DNA appears to allow the backbone the flexibility to assume the full conformation of the long double-helix, which involves not only the basic helix, but additional coiling necessary to fit these very long molecules into the very small volume of a cell nucleus.
In contrast, very similar molecules, containing ribose instead of deoxyribose, and known generically as [[RNA]], are known to form only relatively ''short'' double-helical complementary base paired structures. These are well known, for instance, in [[ribosome | ribosomal]] RNA molecules and in transfer RNA ([[tRNA]]), where so-called ''hairpin'' structures from [[palindrome | palindromic]] sequences within one molecule.
== See also ==
* [[Arabinose]]
* [[Lyxose]]
* [[Ribose]]
* [[Ribulose]]
* [[Xylose]]
* [[Xylulose]]
==References==
<references/>
{{Carbohydrates}}
[[Category:Aldoses]]
[[Category:Deoxy sugars]]
[[Category:Monosaccharides]]
[[cs:Deoxyribosa]]
[[da:Deoxyribose]]
[[de:Desoxyribose]]
[[et:Desoksüriboos]]
[[es:Desoxirribosa]]
[[eo:Desoksiribozo]]
[[fr:Désoxyribose]]
[[it:Deossiribosio]]
[[lt:Dezoksiribozė]]
[[mk:Деоксирибоза]]
[[nl:Deoxyribose]]
[[ja:デオキシリボース]]
[[oc:Desoxiribòsa]]
[[pl:Deoksyryboza]]
[[pt:Desoxirribose]]
[[ru:Дезоксирибоза]]
[[simple:Deoxyribose]]
[[sr:Дезоксирибоза]]
[[fi:Deoksiriboosi]]
[[sv:Deoxiribos]]
[[uk:Дезоксирибоза]]
[[tr:Deoksiriboz]]