sulfaatglycosaminoglycan

Sulfated glycosaminoglycans (sulfated GAGs) are linear, negatively charged polysaccharides composed of repeating disaccharide units that typically contain uronic acid (glucuronic or iduronic) linked to an amino sugar (N-acetylglucosamine or N-acetylgalactosamine), with variable patterns of sulfation. They include chondroitin sulfate, dermatan sulfate, heparan sulfate, heparin, and keratan sulfate. Hyaluronic acid is related but is not sulfated.

In many proteins, these GAG chains are covalently attached to core proteins to form proteoglycans, and their assembly occurs in the Golgi apparatus. Sulfation patterns are introduced by specific sulfotransferases, resulting in diverse motifs that influence binding interactions. The chains are subsequently degraded by lysosomal enzymes.

Sulfated GAGs contribute to the structure and function of the extracellular matrix by retaining water and providing resistance to compression, thereby shaping tissue mechanics. Their negative charge enables interactions with a broad range of proteins, including growth factors, cytokines, chemokines, enzymes, and structural components, which in turn modulate cell signaling, migration, and development. Specific sulfation motifs can alter binding affinities and biological outcomes, such as anticoagulant activity seen with heparin and certain heparan sulfate motifs that potentiate interactions with antithrombin III.

Dysregulation of GAG sulfation or degradation leads to lysosomal storage disorders known as mucopolysaccharidoses. Clinically, sulfated GAGs have therapeutic and material applications, notably heparin as an anticoagulant and various GAG-derived derivatives explored for biomedical uses.