» Not to be confused with bacterial peptidoglycan. Proteoglycans are glycoproteins that're heavily glycosylated. They have a core protein with one or more covalently attached glycosaminoglycan (GAG) chain(s). The chains are long, linear carbohydrate polymers that're negatively charged under physiological conditions, due to the occurrence of sulfate and uronic acid groups. Proteoglycans occur in the connective tissue. Types Proteoglycans can be categorised depending upon the nature of their glyc… (More on Proteoglycan)