<unk>  is a polymer of disaccharides, which are composed of D-glucuronic<unk>  and N-acetyl-D-glucosamine, linked via alternating β-(1→4) and β-(1→3) glycosidic bonds.<unk>  can be 25,000 disaccharide repeats in length. Polymers of<unk>  can range in size from 5,000 to 20,000,000 Da in vivo. The average molecular weight in human synovial fluid is 3–4 million Da, and<unk>  purified from human umbilical cord is 3,140,000 Da; other sources mention average molecular weight of 7 million Da for synovial fluid.<unk>  also contains silicon, ranging 350–1,900μg/g depending on location in the organism.<unk>  is energetically stable, in part because of the stereochemistry of its component disaccharides. Bulky groups on each sugar molecule are in sterically favored positions, whereas the smaller hydrogens assume the less-favorable axial positions.
Hyaluronic acid
Polysulfated glycosaminoglycan
Cerebroside
Glucuronic acid
Lecithin
Hippulin
Pentosan polysulfate
Chaperone 