L-Glucose

L-Glucose
IUPAC name

L-Glucose
Identifiers
Abbreviations L-Glc
CAS number 921-60-8
PubChem 206
EC number 213-068-3
Properties
Molecular formula C6H12O6
Molar mass 180.16 g/mol
Density 1.54 g/cm3
Solubility in water 91 g/100 ml (25 °C)
Hazards
MSDS ICSC 0865
EU Index not listed
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

L-Glucose is an organic compound with formula C6H12O6 or H–(C=O)–(CHOH)5–H, specifically one of the aldohexose monosaccharides. Its molecular structure is an enantiomer of the more common D-glucose.

L-Glucose does not occur naturally in higher living organisms, but can be synthesized in the laboratory. L-Glucose is indistinguishable in taste from D-glucose,[1] but cannot be used by living organisms as source of energy because it cannot be phosphorylated by hexokinase, the first enzyme in the glycolysis pathway. One of the known exceptions is in Burkholderia caryophylli, the enzyme D-threo-aldolse dehydrogenase is capable of oxidising L-glucose[2]

Like the 'D-' isomer, L-glucose usually occurs as one of four cyclic tautomers — α- and β-L-glucopyranose (the most common, with a six-atom ring), and α- and β-L-glucofuranose (with a five-atom ring). In solution, these isomers interconvert in matters of hours, with the open-chain form as an intermediate stage.

Uses

L-Glucose was once proposed as a low-calorie sweetener, but was never marketed due to excessive manufacturing costs.[1]

The L-glucose derivative, L-glucose pentaacetate, was found to stimulate insulin release, and might therefore be of therapeutic value for type 2 diabetes.[3] L-Glucose was also found to be a laxative, and proposed as a colon-cleansing agent which would not produce the disruption of fluid and electrolyte levels associated with the significant liquid quantities of bad-tasting osmotic laxatives conventionally used in preparation for colonoscopy.[4]

References

  1. ^ a b A Natural Way to Stay Sweet, NASA, http://www.sti.nasa.gov/tto/Spinoff2004/ch_4.html, retrieved 2009-09-02 .
  2. ^ Sasajima, K.; Sinskey, A. (1979). "Oxidation of l-glucose by a Pseudomonad". Biochimica et Biophysica Acta (BBA) - Enzymology 571: 120–126. doi:10.1016/0005-2744(79)90232-8.  edit
  3. ^ Malaisse, W. J. (1998), "The riddle of L-glucose pentaacetate insulinotropic action", Int. J. Mol. Med. 2 (4): 383–88, http://www.biomedexperts.com/Abstract.bme/9857221/The_riddle_of_L-glucose_pentaacetate_insulinotropic_action_review .
  4. ^ Raymer, Geoffrey S.; Hartman, Donald E.; Rowe, William A.; Werkman, Robert F.; Koch, Kenneth L. (2003), "An open-label trial of L-glucose as a colon-cleansing agent before colonoscopy", Gastrointest. Endosc. 58 (1): 30–35, doi:10.1067/mge.2003.293, PMID 12838217 .