Polysaccharides molecular structure

By clicking the appropriate buttons on the form, the user can combine molecular structure queries of sample, CSP and solvent, using operators AND, OR, NOT with data queries in one search. A query for the search of chiral separations of alpha-aromatic acids on any polysaccharide phases coated on silica gel providing an alpha value superior to 1.2 is shown in Eig. 4-4. 

Ring-opening polymerization has played an important role in systematic approaches to the chemical synthesis of polysaccharides and the clarification of their biomedically interesting characteristics in relation to their own molecular structures. The early... 

By 1945, Stacey speculated about the possibility of a structural relationship between Pneumococcus capsular polysaccharides and those produced by other organisms. With Miss Schliichterer, he had examined the capsular polysaccharide of Rhizobium radicicolum. This polysaccharide gave a precipitin reaction in high dilution, not only with Type III Pneumococcus antiserum, but also mixed with antisera from other Pneumococcus types. The chemical evidence indicated that the polysaccharide resembled the specific polysaccharides of Types I and II Pneumococcus. A decade later, the acidic capsular polysaccharide from Azoto-bacter chroococcum, a soil organism, was studied. It, too, produced serological cross-reactions with certain pneumococcal specific antisera. Although the molecular structure of the polysaccharide was not established, adequate evidence was accumulated to show a structural relationship to Type III Pneumococcus-specific polysaccharide. This was sufficiently close to account for the Type III serological cross-relationship. 

Polysaccharides Synthesized by Micro-organisms. I. The Molecular Structure of Mannocaralose Produced from Glucose by Penicillium charlesii G. Smith, W. N. Haworth, H. Raistrick, and M. Stacey, Biochem. J., 29 (1935) 612- 621. 

A similar molecular structure is also proposed82 for the gummy polysaccharide from corm sacs of Watsonia pyramidata in which the (1— 4)-xylan backbone is highly substituted with 2- as well as 3-linked L-arabinofuranosyl side... 

The side chains in the latter are flexible disaccharides on account of poor-quality diffraction patterns, their tentative molecular structures are known only from computer modeling.1" On the other hand, well-defined crystal structures are available for gellan and welan, and they can be correlated with the physical properties of the polysaccharides the details are presented here. Their conformation angles are listed in Table VI. 

Although there is no direct evidence that molecular structure and gelation properties show such a close correlation, this hypothesis may help to show that the mechanism of gelation is a very specific reaction analogous to specific biochemical reactions, like antigen-antibody reactions, etc., in which polysaccharides are also involved. 

Molecular Structure. Most starches consist of a mixture of two polysaccharide types amylose, an essentially linear polymer, and amylopectin, a highly branched polymer. The relative amounts of these starch fractions in a particular starch are a major factor in determining the properties of that starch. 

Summarized in Table 2 is the sperm penetration in cervical mucus data as a function of molecular structure for various polysaccharides, with the following observations ... 

Plant structural material is the polysaccharide cellulose, which is a linear p (1 —> 4) linked polymer. Some structural polysaccharides incorporate nitrogen into their molecular structure an example is chitin, the material which comprises the hard exoskeletons of insects and crustaceans. Chitin is a cellulose derivative wherein the OH at C-2 is replaced by an acetylated amino group (—NHCOCH3). Microbial polysaccharides, of which the capsular or extracellular (exopolysaccharides) are probably the most important class, show more diversity both in monomer units and the nature of their linkages. 

The linear, but highly branched, molecular structure of the galactomannans is the reason for some specific properties which are quite different from those of the unbranched cellulose-like and water-insoluble mannans and glucomannans. Galactomannans are hydrated in cold water and give stable solutions even in acidic formulas. The interactions of galactomannans with other polysaccharides are the base of a variety of industrial applications. 

The Gelling Mechanism and Relationship to Molecular Structure of Microbial Polysaccharide Curdlan... 

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