Connective tissue glycosaminoglycan structure

Polysaccharide lyase Family 8 (PL 8). This family encompasses lyases acting upon mammalian connective tissue glycosaminoglycans, and for this reason is the best investigated, with a number of crystal structures available. It has a two-domain fold with an (a/ot)5 toroid connected to a domain almost exclusively of (3-sheet. The reactions catalysed are syn eliminations, with available evidence indicating an irreversible 1cb mechanism, in which the intermediate enolate is stabilised by hydrogen bonding, rather than metal ions, and both deprotonation of C5 and protonation of 04 are carried out by the same tyrosine residue. 

Kariya, Y., Watabe, S., Ochial, Y., Murata, K., and Hashimoto, K. (1990). Glycosaminoglycan involved in the cation-induced change of body wall structure of sea cucumber Stichopus japonicus. Connect. Tissue Res. 25,149-159. 

The ICD of the dyes bound to saccharides through an ionic coupling or hydrophobic interaction may remain a conflicting problem. The side-chain chromophores covalently bound to saccharides permit CD bands in the far or near ultraviolet region. These side-chain chromophores can exhibit CD and thus provide more definitive information on the conformation of saccharide moieties. Thus, acetamide CD has been observed to reflect polymer secondary structure of glycosaminoglycans, which are the connective-tissue proteoglycans. 

Histiotypic The in vitro resemblance, of cells in culture, to a tissue in form or function or both. For example, a suspension of fibroblast-like cells may secrete a glycosaminoglycan-collagen matrix and the result is a structure resembling fibrous connective tissue, which is, therefore, histiotypic. This term is not meant to be used along with the word culture . Thus, a tissue culture system demonstrating form and function typical of cells in vivo would be said to be histiotypic. 

Glycosaminoglycans found in connective tissues are divided in five main classes [3], Their chemical structures are given in Figure 1. 

Connective tissue, which consists primarily of fibroblasts, produces extracellular matrix materials that surround cells and tissues, determining their appropriate position within the organ (see Chapter 49). These materials include structural proteins (collagen and elastin), adhesive proteins (fibronectin), and glycosaminoglycans (heparan sulfate, chondroitin sulfate). The unique structures of the proteins and carbohydrates found within the extracellular matrix allow tissues and organs to carry out their many functions. A loss of these supportive and barrier functions of connective tissue sometimes leads to significant clinical consequences, such as those that result from the microvascular alterations that lead to blindness or renal failure, or peripheral neuropathies in patients with diabetes mellitus. 

Until recently, the work in this area has been insuflScient to warrant its review, but some papers on the biochemistry and pathophysiology of connective tissue (F9) are relevant. In consideration of the reports available, it must be borne in mind that comparisons made outside a particular circle of experiments may be invalid on account of the different conditions of the subjects, and conditions and methods for isolation, separation, and measurement of the macromolecules. Many such methods both for tissues and fluids have been reported (see reviews cited in Section 1.1), and it is imperative to ensure that the isolation and separation processes are effective (see B15, K12). Microscale methods have been devised to function on a few micrograms of material for component analysis (e.g., B16 see K17), but more particularly for the eomplete identification of a glycosaminoglycan on a basis of chemical structure (e.g., B13, B14). 

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