Arabinogalactan
Arabinogalactan, also known as galactoarabinan, larch arabinogalactan, and larch gum, is a
The microbial arabinogalactan is a major structural component of the
The mycobacterial arabinogalactan is recognized by a putative immune lectin intelectin present in chordates.[6]
Structure of microbial arabinogalactan
The reducing end of microbial arabinogalactan consists of the terminal sequence →5)-D-Galf-(1→4)-L-Rhap-(1→3)-D-GlcNAc[citation needed]. A muramyl-6-P is also found within the peptidoglycan functional group. The mycolylarabinogalactan of mycobacteria is attached to the peptidoglycan by the actinomycete-specific diglycosylphosphoryl bridge, L-Rhap-(1→3)-D-GlcNAc-(1→P).[3]
Arabinogalactan contains a galactan chain, with alternating 5-linked β-D-galactofuranosyl (Galf) and 6-linked β-D-Galf residues. The arabinan chains are attached to C-5 of some of the 6-linked Galf residues. There are three major structural domains for arabinan. The first is a domain consisting of linear 5-linked α-D-Araf residues. The second is a domain with branched 3,5 linked α-D-Araf residues substituted with 5-linked α-D-Araf units at both branched positions, and the third is A terminal non-reducing domain for end arabinan consisting of a 3,5-linked α-D-Araf residue substituted at both branched positions with the disaccharide β-D Araf-(1→2)- α-D-Araf. These three arabinan chains are attached to the galactan at residues 8, 10, and 12.[3]
The non-reducing end of arabinogalactan is
Approximately one of the three arabinosyl chains attached to the galactan chain contains
Commercial applications
It is used as a thickener in foods, in cosmetics,[7] and is being studied for possible medical uses.[8][9]
See also
References
- ISBN 978-0-306-46469-0.
- ^
Esko, Jeffrey D.; Tamara L. Doering; Christian R.H. Raetz (2008). in Essentials of Glycobiology. Cold Spring Harbor Press. pp. Ch. 20. ISBN 9780879697709.
- ^ ISBN 978-1-904455-45-5.
- PMID 18303028.
- PMID 16040600.
- PMID 11313366.
- ^ "Galactoarabinan". Australian Industrial Chemicals Introduction Scheme. Australian Department of Health and Aged Care. Retrieved 13 October 2022.
- PMC 4828828.
- ^ D'Adamo, Peter (1996). "Larch Arabinogalactan is a Novel Immune Modulator". J. Naturopath. Med. 4: 32–39.