Mucopolysaccharides

Mucopolysaccharides, also known as glycosamine glycans, are high molecular weight substances (polysaccharides), which are composed of repeating disccharide units (disaccharides), a mostly sulphated amino sugar (N-acetyl-glucosamine or N-acetyl-galactosamine) and usually a uronic acid. Mucopolysaccharides form a gel-like basic substance with high compressive strength and thus define the special biomechanical properties of certain tissues, such as skin, connective tissue and cartilage. Because of the acid groups they contain, these mucopolysaccharides are called acidic mucopolysaccharides.

Mucopolysaccharides are broken down hydrolytically by lysosomal hydrolases.

The genetic defect of these enzymes leads to a reduced degradation of mucopolysaccharides, which manifests itself in deformations of many tissues, especially of the skeleton, the eye and in mental retardation(mucopolysaccharidosis).

4 main groups are distinguished:

• Hyaluronic acid (skin, vitreous body of the eye)
• Chondroitin sulphate C and chondroitin sulphate B = Dermatan sulphate (cartilage, umbilical cord, skin, tendons)
• Keratan sulphate (cartilage, cornea, annulus fibrosus, nucleus pulposus)
• Heparan sulfate

The term glycosamine glycans, which is often used today instead of mucopolysaccharides, was coined because one of the two sugar residues of the repeating disaccharide unit is always derived from an amino sugar (N-acetylglucosamine or N-acetylgalactosamine).

1. Kiga N (2012) Histochemistry for studying structure and function of the articular disc of the human temporomandibular joint. Eur J Histochem 56:e11.