Proteoglycan molecules

There are other glycosaminoglycans. Hyaluronic acid [9004-61-9] occurs both free and in noncovalent association with proteoglycan molecules. Heparin [9005-49-6] and heparan sulfate [39403-40-2] also known as heparitin sulfate [9050-30-0] occur in mast cells and in the aorta, Hver, and lungs. 

Fig. 6.5. A proteoglycan molecule contains a protein core to which numerous carbohydrate (glycosaminoglycan) groups attach. Proteoglycan units can aggregate along a central hyaluronic acid backbone.

Proteoglycan aggregate of cartilage, consisting of a hyaluronic acid (hyaluronate, HA) chain to which proteoglycan molecules are bound non-covalently. [Reprinted by permission from reference [4, Fig. 15]... 

The development of a model for the entire cartilage spectrum, without the use of pure-component spectra, holds much promise because it does not require user intervention. In addition, the incorporation of many (15-i-) factors into a least-squares model may be necessary to describe the interactions between collagen and proteoglycan molecules. Moreover, the incorporation of a parsimony measure to reduce noise contributions in model development may provide a better classification of osteoarthritic-related damage. 

Once the protein sequence has been set up and the protein chain has been produced in intact form, carbohydrate units may be added to complete the formation of a proteoglycan molecule. The biosynthetic aspects of the glycosaminoglycan chain have been studied in considerable detail. 

Pickard, J., Ingham, E., Egan, J., Fisher, J. Investigation into the effect of proteoglycan molecules on the tribological properties of cartilage joint tissues. Proc. Inst. Mech. Eng. 212, 177-182 (1998)... 

Figure 27.1 Arrangement of a proteoglycan molecule with protein core and glycosaminoglycan chains...

Figure 16 A Proteoglycan molecule, shown here, consists of a long protein chain (the core) with attached polysaecharide chains, protruding like bristles, and making up the bulk of the molecule.

Sasada et al. proposed a model named surface gel hydration lubrication in order to explain the lubrication mechanism of cartilages [6,7]. In this study, it was assumed that a part of proteoglycan molecules sticks out of the surface of cartilage and forms the layer of gel hydrated with lubricant. 

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