glúkósamínóglykánum

Glúkósamínóglykánum, often abbreviated as GAG, is a class of linear polysaccharides found in connective tissues of animals. These molecules are composed of repeating disaccharide units, typically consisting of an amino sugar (either N-acetylglucosamine or N-acetylgalactosamine) and a uronic acid (either glucuronic acid or iduronic acid). The amino group is usually sulfated, and one or both sugars in the disaccharide unit may also be sulfated. This high degree of sulfation is a key characteristic of GAGs and contributes to their highly negatively charged nature.

GAGs exist as long, unbranched chains that can be very large, sometimes exceeding hundreds of thousands of daltons. They are highly hydrophilic due to their charged groups, which attract a large number of water molecules. This property allows GAGs to form a hydrated gel-like substance that surrounds cells, providing structural support and lubrication.

There are several major types of GAGs, including hyaluronic acid, chondroitin sulfate, dermatan sulfate, heparin, heparan sulfate, and keratan sulfate. Each type differs in its specific disaccharide composition, sulfation pattern, and the presence or absence of uronic acid. These variations dictate their specific functions within the body. For example, hyaluronic acid is crucial for joint lubrication and tissue hydration, while heparin acts as an anticoagulant. GAGs play vital roles in maintaining tissue integrity, cell signaling, and regulating cell behavior.