Galactosamine

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Structural formula
Structure of D-galactosamine
General
Surname D - (+) - galactosamine
other names
  • α- D- galactosamine
  • 2-amino-2-deoxy- D- galactose
  • Chondrosamine
Molecular formula C 6 H 13 NO 5
Brief description

white solid

External identifiers / databases
CAS number
PubChem 24154
ChemSpider 22576
Wikidata Q375145
properties
Molar mass
  • 179.17 g mol −1
  • 215.61 g mol −1 (hydrochloride)
Physical state

firmly

Melting point
  • 185 ° C (amino sugar)
  • 172–180 ° C (hydrochloride)
solubility

soluble in water (hydrochloride)

safety instructions
GHS labeling of hazardous substances
no GHS pictograms
H and P phrases H: no H-phrases
P: no P-phrases
Toxicological data

2660 mg kg −1 ( LD 50 ,  mouse ,  ip )

As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Galactosamine is the common name of the hexosamine 2-amino-2-deoxy- D- galactose . The amino sugar of galactose is in N- acetylated form (as N-acetylgalactosamine ) a monomer of chondroitin and a component of glycoproteins and glycolipids . The occurrence in cartilage (gr. Chondros ), connective tissue and tendons led to the name chondrosamine .

Occurrence

Hormone - Glycoproteins like Follicle Stimulating Hormone (FSH) or Luteinizing Hormone (LH) contain D- galactosamine.

Galactosamine is mainly marketed as the hydrochloride salt ( D- galactosamine-HCl); the derivative N -acetyl- D- galactosamine also exists.

Functions

The galactosamine hydrochloride is liver damaging in rats, mice and other animals; it is therefore used in animal experiments to stimulate liver damage .

metabolism

Galactosamine is required in various ways in the metabolism, but it often cannot be incorporated directly. An example is the path from D - fructose-6-phosphate to chondroitin sulfate :

  • Fructose-6-phosphate is converted to D - glucosamine-6-phosphate by the enzymes glutamine-fructose-6-phosphate-transaminase ( EC  2.6.1.16 ) or glucosamine-6-phosphate-deaminase ( EC  3.5.99.6 ) .
  • This is due to the enzymes glucosamine-6-phosphate N -acetyltransferase ( EC  2.3.1.4 ) or N -Acetylglucosamin-6-phosphate deacetylase ( EC  3.5.1.25 ) to N -acetyl- D glucosamine converted -6-phosphate.
  • This is converted to N -acetyl- D- glucosamine-1-phosphate by the enzyme phosphoacetylglucosamine mutase ( EC  5.4.2.3 ) .
  • This is incorporated into the nucleotide UDP by the enzyme UDP- N -acetylglucosamine diphosphorylase ( EC  2.7.7.23 ) , resulting in UDP- N -acetyl- D -glucosamine.
  • This is converted into the nucleotide UDP- N -acetyl- D- galactosamine by the enzyme UDP- N -acetylglucosamine-4-epimerase ( EC  5.1.3.7 ) .
  • UDP- N -acetyl- D -Galactosamin is one of the precursors of chondroitin sulfate, which is composed of the monomers N is -Acetylgalactosamin and glucuronic acid.

Individual evidence

  1. ↑ a b c Data sheet D - (+) - Galactosamine hydrochloride from Sigma-Aldrich , accessed on January 7, 2012 ( PDF ).
  2. ↑ a b c Entry on galactosamine. In: Römpp Online . Georg Thieme Verlag, accessed on December 23, 2011.
  3. ↑ Data sheet D-Galactosamine hydrochloride, 98% from AlfaAesar, accessed on December 23, 2011 ( PDF )(JavaScript required) .
  4. ↑ a b Entry on D-galactose, 2-amino-2-deoxy-, hydrochloride in the ChemIDplus database of the United States National Library of Medicine (NLM), accessed on July 31, 2018 or earlier.
  5. ↑ a b Zhongcaoyao. Chinese Traditional and Herbal Medicine. Vol. 11, 1980, p. 262.
  6. ↑ MA Freudenberg et al .: Requirement for lipopolysaccharide-responsive macrophages in galactosamine-induced sensitization to endotoxin ; PMC 260982 (free full text, PDF).
  7. ↑ D. Keppler and K. Decker: Studies on the mechanism of galactose hepatitis: Accumulation og Galactosamine-1-phosphate and its inhibition of UDP-glucose pyrophosphorylase ; doi : 10.1111 / j.1432-1033.1969.tb00677.x .