Glycosaminoglycane
See also: GAG
The glycosaminoglycanes or glycosaminoglycannes (GAG) were indicated a long time under the term of " mucopolysaccharides acides" because of their strong water holding capacity (" muco"), of their glucidic nature (" polysaccharides") and of their acid nature coming from their multiple negative charges (" acides"). They are indeed linear chains (not ramified) sulphated made up of the repetition of a basic diholoside always containing a hexosamine (glucosamine (GlcN) or galactosamine (GalN)) and another ose (glucuronic acid (GlcA), acid iduronic (IdoA), galactose (Gall)). Glucosamine either N-is sulphated (GlcNS), or N-acetylated (GlcNac). The galactosamine N-is always acetylated (GalNac).
They form important Composant S of the conjunctive fabrics.
The chains of GAG can be dependant by Covalence on a Protéine to form Protéoglycane S.
Various types of glycosaminoglycanes
The GAG include/understand:- the chondroïtine sulfate. (elastic cartilage, hyaline cartilage, bone, derm, cornea)
- the dermatane sulfate. (derm, tendon, ligament, fibrous cartilage)
- the kératane sulfate (cartilage, cornea)
- the Heparin /h éparane sulfate (liver, lung, aorta)
- the Hyaluronic acid (Absence of O-sulphating)
Summary table
One distinguishes on the one hand the simple polymers which present only residues of GlcA along their chain (hyaluronic acid, chondroïtine sulfate) and on the other hand the copolymers including/understanding at the same time residues from GlcA and IdoA (heparin, héparane sulfate and dermatane sulfate). One also distinguishes the glucosaminoglycanes from structure N and the galactosaminoglycanes of structure N.
See too
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