Carbohydrate Polymers linear

Carbohydrate polymers are formed from the linear and branched combination of a wide variety of different naturally occurring simple sugars known as monosaccharides. Monosaccharides are a reasonably diverse set of molecular building blocks, each capable of linking to other monosaccharides in a variety of different ways, with the result that the exquisite... 

Thus, ionizing radiation provides an excellent tool to reduce the molecular weight of a carbohydrate polymer whenever required for medicinal application, e.g. in the case of chitosan [83-85]. On the other hand, an increased stability against free-radical induced depolymerization might be required. This may be achieved by chemically crosslinking the native linear polymer the radiolytic behaviour of cross-linked hyaluronic acid, called hylan, has been studied [86]. 

X. Jiang, L. Chen, W. Zhong, A new linear potentiometric titration method for the determination of deacetylation degree of chitosan, Carbohydr. Polym. 54 (2003) 457-463. 

Starch consists of two major components amylose, a mostly linear a-D(l-4)-glucan and amylopectin, an a -D-(l-4)-glucan which has a -D(16) linkages at the branch point. The linear amylose molecules of starch have a molecular weight of 0.2-2 million, whereas the branched amylopectin molecules have molecular weights as high as 100-400 million (18,19) (see POLYSACCHARIDES AND Carbohydrate Polymers). 

Table 1 Some Linear Carbohydrate Polymers Sdurce Common Name Sugars Chain ...

It is estimated that some 10 tons of carbohydrate polymers, mostly cellulose, are produced annually i.e., 25 tons per person on earth. Fortunately, carbohydrate-rich materials including urban refuse, agricultural residues and lignocellulosics are good fermentation substrates, hence microorganisms assure that biosynthesis and decay are in balance. That a major product of nature s biomass transformation should be a high molecular weight linear polyester is perhaps unexpected. 

For the configuration-conformational properties of simple carbohydrates, as well as their reactivities, comprehensive treatises should be consulted (Pigman and Horton, 1972). It has to be mentioned on closing, that recent achievements in macromolecular science have established the ways to the synthesis of linear homopolysaccharides and copolysaccharides (normally by cationic polymerization) of different suitably protected anhydrosugars (Schuerch, 1981). These syntheses open the route to the availability for our studies of a variety of tailor made carbohydrate polymers. A few synthetic polysaccharides have in fact already been used to investigate immunological and allergic reactions in experimental animals and the interaction of plant lectins with carbohydrates (Schuerch, 1981). 

Bizot, H., Le Bail, P., Leroux, B., Davy, J., Roger, P. and Buleon, A. (1997) Calorimetric evaluation of the glass transition in hydrated, linear and branched polyanhydroglucose compounds. Carbohydrate Polymers, 32,... 

The macromolecules of cells are built of units—amino acids in proteins, nucleotides in nucleic acids, and carbohydrates in polysaccharides—that have structural polarity. That is, these molecules are not symmetrical, and so they can be thought of as having a head and a tail. Polymerization of these units to form macromolecules occurs by head-to-tail linear connections. Because of this, the polymer also has a head and a tail, and hence, the macromolecule has a sense or direction to its structure (Figure 1.9). 

---