EN
Proteoglycans can be found in the extracellular matrix of most tissues. They play the role of receptors, take part in cellular adhesion and also interactions between cells. Proteoglycans consist of proteins with one or more covalently bonded glycosaminoglycans. There are seven different types of glycosaminoglycans: hyaluronic acid, heparin and sulphates of chondroitin, keratan I and II, heparin and dermatan. Hyaluronic acid and chondroitin sulphate appear in synovial fluid where they take part in binding water, preventing mechanical stress and increasing elasticity. Keratan sulphate and chondroitin sulphate are used as potential markers of osteoarthritis. Osteoarthritis is a type of arthritis that is caused by the breakdown and eventual loss of the cartilage of one or more joints. Cartilage is a protein substance that serves as a cushion between the bones of the joints. Dermatan sulphate is responsible for the individual resistance to inflammation and pathogens. Understanding the mechanisms of interactions between glycosaminoglycans and pathogens will help to develop more effective vaccinations. The perfect functioning of glycosaminoglycans depends on the efficient activity of both synthesising and degrading enzymes. Even small dysfunctions cause major diseases and disorders.