[Proteoglycans--are distributed throughout the body and have many functions].

Proteoglycans constitute a defined group of carbohydrate-containing proteins. The carbohydrate chains which are denominated glycosaminoglycans contain sulfate and are negatively charged at physiological pH. Proteoglycans are strong polyanions and can bind a long range of macromolecules such as collagen, histamin and antithrombin, and they participate in processes such as regulation of coagulation, maintenance of connective tissue structure, storage of amines intracellularly, and regulation of hemopoesis. Genetic defects in the turnover of proteoglycans lead to conditions known as mucopolysaccharidoses. The best known proteoglycan in the clinic is the antithrombotic agent heparin.