What are proteoglycans?

Proteoglycans are a type of molecule found in the connective tissue of the body. The connective tissue is a fibrous tissue that provides support for other body structures. Proteoglycans form the main part of the extracellular matrix, a material between cells that provide structural support. Unlike other body tissues, the extracellular matrix is ​​the most important part of the connective tissue.

proteoglycans are strongly glycosylated glycoproteins. This means that these are proteins with polysaccharide chains, a type of carbohydrate. A specific type of polysaccharides attached to proteoglycans is called glycosaminoglycans (GAG). Proteoglycans are negatively charged due to the presence of sulphates and uron acids. Proteoglycan chains can be made of chondroitin sulphate, dermatan sulfate, heparin sulphate, heparan sulphate or keratan sulphate.

In addition to the type of gag worked, proteoglycans can be categorized by size. Large Molecules include Aggecan, an important part of the cartilageand versican, located in blood vessels and skin. Small molecules present in various connective tissues include decorin, biglycan, fibromodulin and lumican. Because they are negatively charged, proteoglycans also help attract positive ions or cations such as calcium, potassium and sodium. They also bind water and help in the transmission of water and other molecules through an extracellular matrix.

All proteoglycan components are synthesized in cells. Part of the protein is synthesized by ribosomes that form proteins from amino acids. The protein is then moved to the coarse endoplasmic reticulum (RER). It is glycosylated in the Golgi apparatus, other organelles, in a number of steps.

First, a fastener tetrasaccharide is connected to the protein on which polysaccharides can grow. Then, the sugars are added one by one. When proteoglycan is completed, it leaves the cell through the Secret Balls and enters the ExtRacellular matrix.

The group of genetic metabolic disorders known as mucopolysaccharidosis is characterized by the inability to break down proteoglycans due to absent or non -functional lysosomal enzymes. These disorders lead to proteoglycanic accumulation in cells. Depending on the type of proteoglycan, mucopolysaccharidosis can build symptoms from short figure and hyperactivity to abnormal skeletal growth and mental retardation.