Galactosamine

• α -D -galactosamine
• 2-amino- 2-deoxy- D-galactose
• Chondrosamine

• 7535-00-4 ( amino sugars )
• 1772-03-8 (hydrochloride)

White solid

• 215.61 g.mol -1 (hydrochloride)

Fixed

Soluble in water (hydrochloride)

2660 mg · kg -1 ( LD50, mouse, ip)

Template: Infobox chemical / molecular formula search available

Galactosamine is the trivial name of the hexosamine 2-amino- 2-deoxy- D-galactose. The amino sugars of galactose in N- acetylated form (as N -acetylgalactosamine ) monomer of chondroitin as well as part of glycoproteins and glycolipids. The deposits in cartilage ( gr chondros ), connective tissue and tendons led to the designation chondrosamine.

Occurrence

Hormone glycoproteins such as follicle stimulating hormone ( FSH) or luteinising hormone (LH) comprise D-galactosamine.

Galactosamine is mainly used as the hydrochloride salt (D -galactosamine - HCl) on the market; next to the derivative N- acetyl-D- galactosamine exists.

Functions

The galactosamine hydrochloride is hepatotoxic in rats, mice and other animals; it is therefore used in animal experiments for stimulating liver damage.

Metabolism

Is galactosamine in metabolism variously required, but it can not be installed directly often. As an example, the path from D -fructose -6-phosphate was named to the chondroitin sulfate:

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