Arabinose

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Arabinose
DL-Arabinose.svg
Names
IUPAC name
Arabinose
Other names
Pectinose
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.023.831
EC Number 205-699-8
Properties[1]
C5H10O5
Molar mass 150.13 g/mol
Appearance Colorless crystals as prisms or needles
Density 1.585 g/cm3 (20 ºC)
Melting point 164 to 165 °C (327 to 329 °F; 437 to 438 K)
834 g/1 L (25 °C (77 °F))
-85.70·10−6 cm3/mol
Hazards
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Related compounds
Related aldopentoses
Ribose
Xylose
Lyxose
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

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.[note 1] 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.[2]

A classic method for the organic synthesis of arabinose from glucose is the Wohl degradation.[3]

D-Arabinose
Alpha-D-Arabinofuranose.svg
α-D-Arabinofuranose
Beta-D-Arabinofuranose.svg
β-D-Arabinofuranose
Alpha-D-Arabinopyranose.svg
α-D-Arabinopyranose
Beta-D-Arabinopyranose.svg
β-D-Arabinopyranose

Etymology[edit]

Arabinose gets its name from gum arabic, from which it was first isolated.[4]

Use in biology[edit]

In synthetic biology, arabinose is often used as a one-way or reversible switch for protein expression under the Pbad promoter in E. coli. This on-switch can be negated by the presence of glucose or reversed off by the addition of glucose in the culture medium which is a form of catabolite repression.[5]

Some organic acid tests check for the presence of arabinose, which may indicate overgrowth of intestinal yeast such as Candida albicans or other yeast/fungus species.

Use in foods[edit]

Originally commercialized as a sweetener, arabinose is an inhibitor of sucrase, the enzyme that breaks down sucrose into glucose and fructose in the small intestine.[6] This inhibitory effect has been validated both in rodents and humans.[6][7] Therefore, arabinose could be used in foods to attenuate the peak of glycemic response (see: glycemic index) after the consumption of sucrose. The long-term effects of arabinose consumption on blood glucose parameters such as HbA1c and fasting blood glucose levels are unknown. Foods that contain arabinose are usually designed for prediabetic and diabetic patients. These foods are especially popular in Japan and China, where arabinose is legally used as a food additive.

Arabinose is a potential prebiotic, because it cannot be absorbed by human intestine and could be utilized by probiotics such as bifidobacteria.[8] This claim requires further validation.

See also[edit]

Notes[edit]

  1. ^ For sugars, the D/L nomenclature does not refer to the molecule's optical rotation properties but to its structural analogy to glyceraldehyde.

References[edit]

  1. ^ Weast, Robert C., ed. (1981). CRC Handbook of Chemistry and Physics (62nd ed.). Boca Raton, FL: CRC Press. p. C-110. ISBN 0-8493-0462-8. 
  2. ^ Watson, James (2003). Molecular Biology of the Gene. p. 503. 
  3. ^ Braun, Géza (1940). "D-Arabinose". Org. Synth. 20: 14. ; Coll. Vol., 3, p. 101 
  4. ^ Merriam Webster Dictionary
  5. ^ Guzman LM, Belin D, Carson MJ, Beckwith J. (July 1995). "Tight regulation, modulation, and high-level expression by vectors containing the arabinose PBAD promoter.". J Bacteriol. 177 (14): 4121–30. doi:10.1128/jb.177.14.4121-4130.1995. 
  6. ^ a b Krog-Mikkelsen, Inger; Hels, Ole; Tetens, Inge; Holst, Jens Juul; Andersen, Jens Rikardt; Bukhave, Klaus (2011-08-01). "The effects of L-arabinose on intestinal sucrase activity: dose-response studies in vitro and in humans". The American Journal of Clinical Nutrition. 94 (2): 472–478. ISSN 1938-3207. PMID 21677059. doi:10.3945/ajcn.111.014225. 
  7. ^ Seri, K.; Sanai, K.; Matsuo, N.; Kawakubo, K.; Xue, C.; Inoue, S. (1996-11-01). "L-arabinose selectively inhibits intestinal sucrase in an uncompetitive manner and suppresses glycemic response after sucrose ingestion in animals". Metabolism: Clinical and Experimental. 45 (11): 1368–1374. ISSN 0026-0495. PMID 8931641. doi:10.1016/s0026-0495(96)90117-1. 
  8. ^ Degnan, B. A.; Macfarlane, G. T. "Transport and metabolism of glucose and arabinose in Bifidobacterium breve". Archives of Microbiology. 160 (2): 144–151. ISSN 0302-8933. doi:10.1007/BF00288717.