Hyaluronic acid, structure

Hyaluronic Acid Structure, Biological Functions and Clinical Applications... 

See also Biosynthesis of Glycoconjugates, Glycoproteins (from Chapter 9), Glycosaminoglycans, Hyaluronic Acid, Structural Polysaccharides, UDP-N-Acetylgalactosamine... 

The Structure of the Hyaluronic Acid Component of Synovial Fluid in Rheumatoid Arthritis," S. A. Barker, S. H. I. Bayyuk, J. S. Brimacombe, C. F. Hawkins, and M. Stacey, Clin. Chim. Acta, 9 (1964) 339-343. 

Hyaluronic acid is a linear polysaccharide found in the highest concentrations in soft connective tissues where it fills an important structural role in the organization of the extracellular matrix (23,24). It has been used in ophthalmic preparations to enhance ocular absorption of timolol, a beta blocker used for the treatment of glaucoma (25), and in a viscoelastic tear formulation for conjunctivitis (26). The covalent binding of adriamycin and daunomycin to sodium hy-aluronate to produce water-soluble conjugates was recently reported (27). 

Hyaluronic acid and collagen are the two main structural components. The collagen is similar to that found in cartilage, consisting of three alpha-chains and known as type II collagen, although subtle differences are now recognized (Swann and Constable, 1972 Swann, 1980). 

Fig. 19 Structures of glycosaminoglycans (A) chondroitin-4-sulfate (B) heparin sulfate (C) dermatin sulfate (D) hyaluronic acid (E) chondroitin-6-sulfate (F) keratin sulfate. 

The Structure of Hyalobiuronic Acid and of Hyaluronic Acid from... 

Huntsman solvent-based collection and refining system, 15 506 Huron-Dow process, 14 42, 53 Huygens principle, 17 424 H values, 23 284 Hyaluronan, 20 577 Hyaluronic acid, 4 706 20 456 classification by structure, 4 723t function as ingredient in cosmetics, 7 829t... 

More complex polysaccharides play important roles in connective tissues and elsewhere. For example, hyaluronic acid is universally present in connective tissues of animals, as well as in their vitreous and synovial fluids. It helps to provide the fluids present in joints with shock-absorbing and lubricating properties. Unlike cellulose, chitin, starch, and glycogen, hyaluronic acid contains two different monomers glucose and N-acetylglucosamine alternate in the structure. Thus, hyaluronic acid is a regular alternating copolymer ABABABA —... 

Fig. 2 Structures of the major and minor disaccharide sequences of heparin and heparan sulfate as well as the major disaccharide units of chondroitin sulfate, dermatan sulfate, keratan sulfate, and hyaluronic acid, where Ac is acetyl.

With an approximate volume of 4 ml, the vitreous is the largest structure within the eye. It has a refractive index of 1.33 and consists of 98-99% water with a scaffold of collagen fibres and macromolecules of hyaluronic acid winding through the scaffold. The healthy human vitreous does not contain blood vessels and has a consistency comparable to that of egg white. 

Model building in the computer is used to analyze the conformational effects of steric interactions between atoms of the polymer skeleton for x-carrageenan, t-carrageenan, A-carrageenan, agar, chondroltin, chondroitin sulfates, dermatan sulfate, keratan sulfate, hyaluronic acid, and related polysaccharides. Over 99% of the conformations are thus excluded and virtually all of the remainder for each polysaccharide lie close together. Predictions are also made from disaccharide crystal structures and checked against experimental results. 

Biosynthetic studies on the formation of hyaluronic acid have yielded less information than have similar studies about the structure of chondroitin. Addition to small, well defined oligosaccharides has not been found. Using labelled nucleoside 5 -glycosyl diphosphates in a bacterial system, evidence has been obtained for the synthesis of hyaluronic acid of high molecular... 

Structure of the repeating unit of hyaluronic acid GlcUA/3(l, 3)GlcN Ac/3( 1,4). 

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