Arabinogalactan
- ( )- Arabinogalactan
- Galactoarabinan
- Lärchenarabinogalaktan
- Arabinogalactan
- Larch gum
- Polyarabinogalactan
- Larch arabinogalactan
Biopolymer
Light brown, odorless solid
Fixed
> 200 ° C
Very well in water about 50 g / l
( Arabinogalactan )
Arabinogalactan is a heteroglycan from plants and mycobacteria. It depends, among other things in gum arabic and gum Ghatti ago.
Properties
Herbal arabinogalactans
Arabinogalactan is a highly branched polysaccharide, consisting of a galactan backbone with side-chains of galactose and arabinose. It is a dietary fiber source and is approved by the FDA since 1998 as Generally Recognized As Safe (GRAS ). It increases the number of Lactobacillus in the intestinal flora and lower the ammonia concentration in the feces. Arabinogalactan in mice reduces the number of monocytes and granulocytes in the spleen, and increased the number of NK cells in the spleen. Arabinogalactan from Larch is a activation of NK cells relative to tumor cells in cell culture with elevated levels of interferon - γ, tumor necrosis factor - α, interleukin- 1β and interleukin -6, of which only IFN- γ activated NK cells.
Arabinogalactans from Siberian larch can reduce the occurrence of colds due to their immunostimulatory properties, and enhance the effect of some vaccines.
Bacterial arabinogalactans
Microbial arabinogalactan is a major constituent of the mycobacterial cell wall, often in the bound glycoproteins. Both galactose and arabinose come here exclusively in furanose form. The galactan portion has a linear structure from about 30 galactoses and is verzewigt via β - (1-5) and β - (1-6) -glycosidic bonds. Which consists of 30 Arabinankette Arabinosen and is connected at three points to the Galactankette, probably due to arabinose 8, 10 and 12 of the arabinogalactan fraction of arabic is a branched polysaccharide, which is terminal-modified with mycolic acids. The glycosidic linkages of the Arabinananteils are α - (1-3), α ( 1-5), and β - (1-2).
The reducing end of the mycobacterial arabinogalactan is composed of the sequence → 5 )-D- Galf - (1 → 4 )-L- Rhap - (1 → 3 )-D- GlcNAc. A muramyl -6- phosphate is located in the peptidoglycan functional group. Mykolylierte the arabinogalactan is connected by the Actinomycetaceae typical link - L- Rhap - (1 → 3 )-D- GlcNAc - (1 → P ) to the peptidoglycan. Arabinogalactan contains Galactankette with alternate linkages ( 5 -linked β -D - galactofuranosyl ( Galf ) and 6 -linked β -D - Galf ). The arabinan chains are attached to the C5 of the 6 -linked β -D - Galf. The arabinan can be divided into three areas. The first area consists of linear 5 -linked α -D - Araf. Said second portion is branched with 3,5- linked α -D - Araf which each carry a 5 -linked α -D - Araf on both branches. The third region comprises 3,5- linked α -D - Araf which both branches the disaccharide β -D - Araf -(1 → 2) - α -D - Araf having (C8, C10 and C12 ).
The non-reducing end of mycolic acids associated with the cell wall. The mycolic acids are linked via the 5- hydroxyls of the last two Araf, usually four mycolic acids on the Pentaarabinosyl portion ( β - Araf - ( 1 → 2) - α - Araf ) 2-3,5 - α - Araf which a two -thirds coverage of the possible positions corresponds.
Approximately one of the three arabinose linkages at the Galactankette contains up to three succinyl groups, mostly. Amino sugars are not succinylated. Mycobacterium tuberculosis in the positively charged and negatively charged amino sugar Succinyle in the central region of the Arabinananteils come more closely to the O- 2 of the inner 3,5- α -D - Araf. The Succinyle are on the chain without mycolic acid.