Heparan sulfate

Heparan sulfate is a mucopolysaccharide (glycosaminoglycan) in which glucuronic acid or L-iduronic acid is glycosidically linked to N-acetylglucosamine. It can also be counted to the group of heparins. They are important components of the extracellular matrix and are found in the plasma membranes of animal cells.
Heparan sulfates can bind massive amounts of water and are therefore, like the other mucopolysaccharides (see below hyaluronic acid), jointly responsible for the special mechanical properties of the extracellular matrix. In addition, heparan sulphate has an anticoagulant effect as a heparin derivative (see heparinbelow).

Sanfilipposchen's disease, a form of mucopolysaccharidoses, is characterized by an autosomal recessive inherited defect in the genes for the enzymes heparan sulfatase (MPS type IIIA; gene locus 17q25.3), N-acetylglucosaminidase (MPS type IIIB; gene locus: 17q21), acetyl-CoA-glucosamine-acetyltransferase (MPS type IIIC; gene locus chromosome 14) or N-acetylglucosamine-6-sulfatase (MPS type IIID; gene locus 12q14). All 4 enzyme defects cause the excessive lysosomal deposition of heparan sulfate in the connective tissue and especially in the CNS (see there).

Hunter's disease is characterized by an X-linked (recessive) inherited mutation of the iduronidase sulfatase gene (gene locus: Xq28). Due to the iduronidase sulfatase defect, dermatan sulfate (= chondroitin sulfate B) and heparan sulfate are deposited in the skin and in internal organs.

1. Patel VN et al (2016) The function of heparan sulfate during branching morphogenesis. Matrix Biol pii: S0945-053X(16)30128-7.
2. Ushiyama A et al (2016) Glycocalyx and its involvement in clinical pathophysiologies. J Intensive Care 4:59.