Ribose

D-Ribose
IUPAC name
D-Ribose
Identifiers
CAS number 50-69-1 YesY
PubChem 5779
EC-number 200-059-4
Properties[1][2]
Molecular formula C5H10O5
Molar mass 150.13 g/mol
Appearance white solid
Melting point

95 °C, 368 K, 203 °F
Solubility in water very soluble
Chiral rotation [α]D −21.5º (H2O)
Related compounds
Related aldopentoses Arabinose
Xylose
Lyxose
Related compounds Deoxyribose
 YesY (what is this?)  (verify)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Ribose is an organic compound with formula C5H10O5; specifically, a monosaccharide (simple sugar) with linear form H-(C=O)-(CHOH)4-H, which has all the hydroxyl groups on the same side in the Fischer projection.

The term may refer to any of two enantiomers: almost always to D-ribose, which occurs widely in nature and is discussed here; or to its synthetic mirror image L-ribose, which is not found in nature and is of limited interest.

D-ribose was first reported in 1891 by Emil Fischer. It comprises the backbone of RNA, a biopolymer that is the basis of genetic transcription. It is related to deoxyribose, as found in DNA. Once phosphorylated, ribose can become a subunit of ATP, NADH, and several other compounds that are critical to metabolism.

Contents

Structure

Ribose is an aldopentose, that is a monosaccharide containing five carbon atoms that, in its open chain form, has an aldehyde functional group at one end. In the conventional numbering scheme for monosaccharides, the carbon atoms are numbered from C1' (in the aldehyde group) to C5'. The deoxyribose derivative, found in DNA, differs from ribose by having a hydrogen atom in place of the hydroxyl group in carbon C2'.

Like many monosaccharides, ribose occurs in water as the linear form H-(C=O)-(CHOH)4-H and any of two ring forms: ribofuranose ("C3'-endo"), with a five-membered ring, and ribopyranose ("C2'-endo"), with a six-membered ring. The ribofuranose form is predominant.

The "D-" in the name D-ribose refers to the stereochemistry of the chiral carbon atom farthest away from the aldehyde group (C4'). In D-ribose, as in all D-sugars, this carbon atom has the same configuration as in D-glyceraldehyde.

Phosphorylation

In biology, D-ribose must be phosphorylated by the cell before it can be used. Ribokinase catalyzes this reaction by converting D-ribose to D-ribose 5-phosphate. Once converted, D-ribose-5-phosphate is available for the manufacturing of the amino acids tryptophan and histidine, or for use in the pentose phosphate pathway. The absorption of D-ribose is 88-100% in the small intestines (up to 200mg/kg/hr). [3]

Use as a supplement

D-ribose is often marketed as a supplement for bodybuilders with a common recommended daily dose being 5 g. Some studies have found no evidence that there is a benefit, while others have found increased endurance, recovery and muscle output in healthy individuals. As a supplement, it is often referred to as Corvalen, a brand name under which it was popularized.

D-ribose has also been used to reduce fatigue in fibromyalgia (FM) and chronic fatigue syndrome (CFS). A 2006 uncontrolled pilot study suggested that D-ribose (5 g three times a day) may be effective in the treatment of FM and CFS.[4] The authors reported that 66% of the 41 participants noted the supplement as being helpful and in improving energy, sleep, mental clarity, pain intensity, and well-being. However, due to the lack of a control group, further study is required to rule out a placebo effect.

D-ribose has been found to be effective in the management of symptoms from myoadenylate deaminase deficiency, a metabolic disorder affecting the skeletal muscles. Myoadenylate deaminase deficiency (MADD). MADD is a genetic disease present in 1-2% of those with European descent. Its symptoms include muscle pain, exercise intolerance and fatigue, treated using ribose. [5]

Ribose is used as a natural anti-anxiety and stress relief ingredient. It is also used to control stress-related eating and drinking that has the added value of being non-sedating with potential anti-depressant properties.

References

  1. ↑ The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals (11th ed.), Merck, 1989, ISBN 091191028X , 8205.
  2. ↑ Weast, Robert C., ed. (1981), CRC Handbook of Chemistry and Physics (62nd ed.), Boca Raton, FL: CRC Press, p. C-506, ISBN 0-8493-0462-8 .
  3. ↑ [1]
  4. ↑ Teitelbaum, Jacob E.; Johnson, Clarence; St. Cyr, John (2006), "The use of D-ribose in chronic fatigue syndrome and fibromyalgia: a pilot study", J. Altern. Complement. Med. 12 (9): 857–62, doi:10.1089/acm.2006.12.857, PMID 17109576 .
  5. ↑ [2]