glükosaminoglükaaniks

Glükosaminoglükaaniks, also known as glycosaminoglycans (GAGs), are long, unbranched polysaccharide chains. They are a crucial component of the extracellular matrix in animal tissues. GAGs are characterized by repeating disaccharide units, where one sugar is an amino sugar (either N-acetylglucosamine or N-acetylgalactosamine) and the other is typically a uronic acid (glucuronic acid or iduronic acid). The presence of sulfate groups attached to the sugar residues is a defining feature of most GAGs, contributing to their highly negatively charged nature.

These negative charges cause GAGs to attract and retain large amounts of water, forming a hydrated gel. This property is essential for their functions, which include providing structural support, lubrication, and shock absorption in connective tissues like cartilage, tendons, and skin. Different types of GAGs exist, each with a specific structure and distribution in the body. Examples include hyaluronic acid, chondroitin sulfate, dermatan sulfate, keratan sulfate, and heparin/heparan sulfate. Hyaluronic acid is unique in that it does not contain sulfated sugars and is not typically found covalently linked to proteins.

The diverse roles of GAGs extend beyond structural support. Heparin and heparan sulfate, for instance, are involved in blood coagulation and cell signaling. Chondroitin sulfate and keratan sulfate are major components of cartilage, contributing to its resilience and ability to withstand mechanical stress. The sulfation patterns and chain lengths of GAGs are highly specific and play a critical role in their interactions with other molecules, such as proteins, growth factors, and receptors, influencing various biological processes.