All Glycosaminoglycans Contain Which of the Following

Question

All glycosaminoglycans contain which of the following?
A)a sulfate ester
B)a $\beta$(1$\to$4)glycosidic bond
C)a carboxylate
D)an amine group that is either acetylated or sulfated
E)all of the above

Accepted Answer

Glycosaminoglycans are composed of repeating disaccharide units, which contain an amino sugar (glucosamine or galactosamine) and a uronic acid (glucuronic acid or iduronic acid). These disaccharides can be acetylated or sulfated at various positions, including the amine group, which gives rise to the variability in glycosaminoglycan structure. Therefore, all glycosaminoglycans contain an amine group that is either acetylated or sulfated. Sulfate esters and carboxylates may be present but not all glycosaminoglycans have them. The specific glycosidic bond mentioned in choice B is not a feature shared by all glycosaminoglycans.