Most important among the matrix proteins are the collagens, elastin, laminins, fibronectin as well as GAG decorated proteoglycans (PGs). Extracellular matrices (ECM) represent a complex network of proteins and glycosaminoglycans (GAGs) constituting the cell microenvironment including elastin, laminins, fibronectin, and GAG decorated proteoglycans (PGs). Except for keratan, the repeating unit consists of an amino sugar, along with a uronic sugar or galactose. Glycosaminoglycans (GAGs) or mucopolysaccharides are long linear polysaccharides consisting of repeating disaccharide (double sugar) units. Because GAGs are highly polar and attract water, they are used in the body as a lubricant or shock absorber. Proteoglycans and glycosaminoglycans—versatile multifunctional integrators of signal transduction and extracellular matrix function. The specific type of polysaccharides attached to proteoglycans are called glycosaminoglycans (GAGs). This means that they are proteins with chains of polysaccharides, a kind of carbohydrate, attached. The key difference between proteoglycans and glycosaminoglycans is that proteoglycans are organic compounds containing a protein bound to a mucopolysaccharide whereas glycosaminoglycans are mucopolysaccharides containing a number of disaccharide repeating units.. Proteoglycans and glycosaminoglycans are biochemical compounds that can be found in our body. PGs are composed of independent structural domains, the sequences and arrangements of which are highly conserved and discretely glycosylated, thus determining a varying … Proteoglycans are glycoproteins of cell surfaces and the ECM which are characterized by the covalent modification with a carbohydrate chain of the GAG type . Proteoglycans (PGs) are glycoconjugates in which a protein or peptide core is substituted with polysaccharide chains known as glycosaminoglycans (GAGs). Glycosaminoglycans are unbranched polysaccharides composed of repeating units of alternating uronic acids and amino sugars. Glycosaminoglycans and Proteoglycans Vitor H. Pomin 1 and Barbara Mulloy 2,* 1 Program of Glycobiology, Institute of Medical Biochemistry Leopoldo de Meis and University Hospital Clementino Fraga Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-913, Brazil; pominvh@bioqmed.ufrj.br 2 Glycosciences Laboratory, Department of Medicine, Imperial College … Proteoglycans are heavily glycosylated glycoproteins. Extracellular matrices (ECM) represent a complex network of proteins and glycosaminoglycans (GAGs) constituting the cell microenvironment. The GAG chains of a proteoglycan may be … Proteoglycans are negatively charged because of the presence of sulfates and uronic acids. Most glycosaminoglycans are covalently attached to core proteins to form proteoglycans.