Connective tissue keratan sulfate

As shown in Figure 48-8, the keratan sulfates consist of repeating Gal-GlcNAc disaccharide units containing sulfate attached to the 6 position of GlcNAc or occasionally of Gal. Type 1 is abundant in cornea, and type II is found along with chondroitin sulfate attached to hyaluronic acid in loose connective tissue. Types I and II have different attachments to protein (Figure 48—8). 

Some disorders may cause an abnormal excretion of GAGs in urine. Among those are various bone diseases, connective tissue diseases, hypothyroidism, urinary dysfunction, and aspartylglucosaminuria. Faint spots for keratan sulfate can also be found in spondyloepiphyseal dysplasia as well as in type II mucohpidoses, where traces of dermatan sulfate may additionally be visible. Furthermore, heparin and tris(hydroxymethyl)aminomethane (Trometamol) can interfere with electrophoretic patterns [56]. To provide a good interpretation of results the clinical features of the patient and the current therapy have to be known. Furthermore, a study of the urin-... 

Keratan sulfate constitutes approximately half the total mucopolysaccharide fraction of bovine cornea, where it was isolated originally by Meyer et al. (M16). It occurs fairly widely in animal connective tissues, and its presence has been reported in nucleus pulposus (G2), aorta (B17), and costal cartilage (M20). Unlike the acid mucopolysaccharides described previously, keratan sulfate contains no uronic acid residue but is comprised of V-acetyl-n-glucosamine, D-galactose, and sulfate, in equimolar ratio. The small amount of L-fucose detected in acidic... 

Note Keratin is an intracellular filamentous protein whereas keratan is a sulfated polysaccharide found extracellularly in cartilage and dermal (stromal) connective tissue. 

Keratan sulfates (Figure 9.23) are a class of structural glycocsaminoglycans found in connective tissue of vertebrates. 

The hydrodynamic resistance of solutions of connective-tissue polysaccharides has been measured by sedimentation techniques [9] the resistance is expressed as the hydraulic conductivity (k), which was defined in Equation 6-9 (Figure 6.8). This analysis permitted the identification of two different groups of polysaccharides those compounds containing Pi 4- and y6i 3-link-ages (such as chondroitan sulfate, keratan sulfate, and hyaluronate) had lower hydraulic resistance than compounds containing some fraction of... 

The physical and mechanical properties of cartilage are certainly important for the physiological role of this tissue. Proteoglycan in connection with collagen and other constituents of this tissue may affect its physical properties. Cartilage proteoglycan is a complex species. To a protein core, many chondroitin sulfate and keratan sulfate chains are attached. 

The ECM refers to the connective tissue that surrounds mesenchymal cells and to the basement membrane (BM) that encompasses parenchymal cells. The ECM contains a large variety of PGs, including members of the aggrecan family, which interact with hyaluronan, and of the decorin family, which have leucine-rich repeats. However, the former are predominantly chondroitin sulfate or keratan sulfate PGs. These PGs can be major tissue constituents, such as aggrecan in cartilage or decorin in tendon. Interestingly, the HSPGs in the ECM are mostly restricted to BMs. 

Hyaluronic acid (HA), a high molecular weight (MW) biopolysaccharide, was discovered by Meyer and Palmer in 1934 in the vitreous humour of cattle eyes [2]. HA is a member of a group of similar polysaccharides that have been termed connective tissue polysaccharides , mucopolysaccharides , or glycosaminoglycans . These polysaccharides include chondroitin sulfate, dermatan sulfate, keratan sulfate, heparan sulfate, and heparin. HA is a... 

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