Polysaccharides methods in structural chemistry

Methods in Structural Polysaccharide Chemistry, 15, 53-89 Brady, Robert F., Jr., Cyclic Acetals of Ketoses, 26, 197-278 Bray, H. G., D-Glucuronic Acid in Metabolism, 8, 251-275... 

Bouveng, H. O., and Lindbero, B., Methods in Structural Polysaccharide Chemistry, 16, 53-89... 

Bourne, E. J. See also. Barker, S. A. Bouveng, H. O., and Lindberg, B., Methods in Structural Polysaccharide Chemistry, 15, 53-89 Brady, Robert F., Jr., Cyclic Acetals of Ketoses, 26, 197-278 Bray, H. G., D-Clucuronic Acid in Metabolism, 8, 251-275 Bray, H. G., and Stacey, M., Blood Group Polysaccharides, 4, 37-55 Brimacombe, j. S. See How, M. J. Butter worth, Roger F and Hanes-siAN, Stephen, Tables of the Properties of Deoxy Sugars and Their Simple Derivatives, 26, 279-296... 

The methylation technique is of outstanding importance in structural polysaccharide chemistry. The procedure involves the preparation of the exhaustively methylated polysaccharide, hydrolysis to a mixture of monomers, and the separation, identification, and quantitative estimation of the components of this mixture the original points of substitution wiU correspond to the unsubstituted hydroxyl groups in these monomeric methyl ethers. Although laborious and time-consuming, the method gives valuable... 

In addition to the above methods, which are of general application in structural polysaccharide chemistry, a number of procedures should be mentioned which either give more limited information or can be applied only in special cases. 

Only a few methods for the specific degradation of polysaccharides were known when an earlier article on structural polysaccharide chemistry appeared in this Series.3 The Smith degradation,4 which has become the most frequently used, had only just been introduced. Since then, a number of specific degradation techniques have been developed. In addition, there have also been some modifications and improvements to existing methods. In this article, chemical methods for specific or selective degradation of polysaccharides, and their applications in structural analysis, will be discussed. Enzymic methods, which may be of considerable value, have already been treated in this Series.5... 

In examining the structure of a polysaccharide, it is convenient to consider the methods involved under the three main headings (a) quantitative analysis, (b) methylation, and (c) periodate oxidation. These techniques may be supplemented by partial or enzymic hydrolysis as the circumstances indicate. Each of these aspects of polysaccharide chemistry may be aided by the application of gas-liquid chromatography, either qualitative or quantitative, or both. Thus, separations impossible by other techniques may often be achieved, and analytical data obtained in a fraction of the time demanded by other methods. 

An article by Barreto-Bergter (Rio de Janeiro, Brazil) and Gorin (Saskatoon, Canada) likewise invokes strong emphasis on n.m.r. methods for structure determination, in this instance by use of carbon-13 techniques in delineating the structural chemistry of polysaccharides from fungi and lichens. 

Lignin is synthesised in plants from monomeric molecnles, whose functionality varies from two to four. Thus, both branched chain and the crosslinked structure may be formed. In plant tissue, the polymer chains of lignin are snrronnded by macromolecules of noncellulosic polysaccharides, with which they form an amorphous lignocarbohydrate matrix. The experimental methods that allow the stndy of the complex topology of macromolecules in a multicomponent solid composite are very limited. Therefore, most of the data are interpreted using theoretical methods developed from polymer chemistry. 

Details of a number of established chemical methods used in determining various aspects of the fine structures of polysaccharides-for example, the specific degradation of polysaccharides containing uronic acid residues by base-catalysed elimination, the location of acyl substituents, and the distribution of singleunit side-chains of D-galactose in galactomannans by alkaline hydrolysis of 6-deoxy-6-(4-tolylsulphonyl)hexopyranosides -are reported in the latest volume in the series Methods in Carbohydrate Chemistry . 

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