| >> Glycosaminoglycans |
The extracellullar matrix present in multicellular organisms consists of fibrous proteins
embedded in hydrated polysaccharide gels. Glycosaminoglycans (GAGs) are polysaccharides
that form a major part of this matrix. GAGs are negatively charged disaccharide repeating
units, covalently linked to "core" proteins. They are copolymers of alternating
hexosamine (D-Glucosamine/D-Galactosamine) and either L-iduronic acid or D-Galactose.
Grouping dependent on the hexosamine residue results in the classification of GAGs as either
Glucosaminoglycans or Galactosaminoglycans.
Click a structure name below to view it in 3D.
|
| Glucosamino |
| | Hyaluronic Acid | b-d-GlcA-(1-3)-b-D-GlcNAc | 1-4 | none |
| | Keratan Sulphate | b-d-Gal-(1-4)-b-D-GlcNAc | 1-3 | C6 (both sugars) |
| | Heparan Sulphate | a-L-IdoA-(1-4)-a-D-GlcN (~30%)
b-D-GlcA-(1-4)-a-D-GlcN (~70%) | 1-4 | 1 or 2 per tetrasacch. N2, O6, and occ. O3 of GlcN; O2 of IdoA/GlcA; N2 of GlcN may be acetylated |
| | Heparin | a-L-IdoA-(1-4)a-D-GlcN (~80%)
b-D-GlcA-(1-4)-a-D-GlcN (~20%) | 1-4 | 4-6 per disacch.; N2 and O6 of GlcN; occ. O3 of GlcN; O2 of IdoA/GlcA |
| Galactosamino |
| | Chondroitin | b-D-GlcA-(1-3)-b-D-GalNAc | 1-4 | O4, O6 of GalNAc; occ. O2, O3; C2 of GlcA |
| | Dermatan Sulphate | b-D-GlcA-(1-3)-b-D-GalNAc
a-L-IdoA-(1-3)-b-D-GalNAc | 1-4 | O4 of GalNAc; O2 of IdoA |
