glucosaminoglycans

Glucosaminoglycans or Gag’s are structures consisting of a proteoglycans-associated hyaluronic acid molecule. They are part of the amorphous or basic substance of the extracellular Matrix and are present only in tissues that you have. * Deficiency or deficiency of these molecules leads to numerous diseases, including Osteoarthritis, fibromyalgia, joint instability, etc. * ..…

In the box we see an increase in the thin reticular structure of proteoglycans and Gags.

This is an “aerial photograph” of a histological preparation of the extracellular Matrix. In the middle of the image we see the cells of the organ surrounded by their basallamina, on the right side of the network of proteoglycans and GAG’s.

Glucosaminoglycans (GAGs) are the most common Heteropolysaccharides in the body. These molecules are long Polysaccharide without branching, and contain repetitions of a disaccharide unit. Disaccharide units contain one of two modified sugars, N-acetylgalactosamine (GaINAc) or N-acetylglucosamine (GlcNAc) and a uric acid such as glucuronate or iduronate. GAGs are negative molecules with an extended Form that provides a high viscosity for a solution. GAGs are located primarily on the surface of the cells or in the extracellular Matrix (MEC). In addition to the viscosity that GAGs offer, a low compressivity can be observed, which is ideally suitable as a lubricating fluid in the joints. At the same time, its rigidity provides the cells with structural integrity and enables cell migration. Specific GAGs with physiological significance are hyaluronic acid, dermatan sulfate, condroitin sulfate, Heparin, heparan sulfate and Keratan sulfate. Although each GAG has a dominant Disaccharide component (see table below), there is a heterogeneity between the sugars of each GAG type.

glucosaminoglycans

Hyaluron is unique in GAGs because it does not contain sulphate and is not covalently bound to a Protein such as proteoglycan. However, if it is part of the facilities that are not covalently formed with proteoglycan in MEC. Hyaluronic acid polymers are very large (with a molecular weight of 100,000 to 10,000,000) and can displace a large volume of water. This property allows them to act as a lubricant and shock absorbent materials.

Proteoglycan

Most GAGs in the body are bound to Central proteins and form proteoglycans (also known as mucopolysaccharides). These GAGs extend at right angles from the center like a brush type. The Binding of GAGs to the central protein comprises a specific Trisaccharide consisting of two galactose residues and an Xylose residue (gag–GalGalXyl–O–CH2 Protein). The binding trisaccharide is linked through an O-glycosidic bond to a S residue in the Protein to the Central Protein. Certain forms of keratansulfaten are bound through an n-asparaginyl bond to the Central Protein. The core proteins in Proteoglycans are rich in S-and T-residues, which enables the entry of several GAG.

Proteoglycan

Clinical Relevance

Proteoglycans and GAGs perform several important functions in the body, some of which have not yet been investigated.One of the features that has already been established, heparin is its role in preventing blood clotting.Heparin is rich in the granules of mast cells along the blood vessels. The release of heparin, these granules in response to an injury and their income by taking serum leads to inhibition of blood clotting as follows: the heparin-free form a complex and simultaneously activates at antithrombin III, which in turn inhibits all serine proteases of the coagulation cascade. This phenomenon is clinically beneficial for the use of injecting Heparin for the treatment of anticoagulant therapies.

Several genetic diseases, such as lysosomal storage disease, result from deficiencies in lysosomal enzymes, which are responsible for the metabolism of membrane-associated GAGs. Such as Mucopolysaccharidosis (MPS) referred to diseases (based on an earlier term, mucopolysaccharide, used for glucosamine glucosaminoglycans) lead to an accumulation of GAGs in the lysosomes of the affected cells. There are at least 14 types of diseases associated with lysosomal storage that affect GAG catabolism. Some of the most common examples are listed in the following table. All these disorders, with the exception of Hunter syndrome (x-bound inheritance), are inherited in a recessive manner on their own. To see a diagram of the localisation of enzyme defects in Gag degradation, go to the mucopolysaccharidosis page.