Keratan sulfate

Keratan sulfate (KS), also called keratosulfate, is any of several sulfated glycosaminoglycans (structural carbohydrates) that have been found especially in the cornea, cartilage, and bone. It is also synthesized in the central nervous system where it participates both in development and in the glial scar formation following an injury. Keratan sulfates are large, highly hydrated molecules which in joints can act as a cushion to absorb mechanical shock.

Like other glycosaminoglycans keratan sulfate is a linear polymer that consists of a repeating disaccharide unit. Keratan sulfate occurs as a proteoglycan (PG) in which KS chains are attached to cell-surface or extracellular matrix proteins, termed core proteins. KS core proteins include Lumican, , Mimecan, Fibromodulin, PRELP, Osteoadherin and Aggrecan.

The basic repeating disaccharide unit within keratan sulfate is -3Galβ1-4GlcNAcβ1-. This can be sulfated at carbon position 6 (C6) of either or both the Gal or GlcNAc monosaccharides. However, the detailed primary structure of specific KS types are best considered to be composed of three regions:

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