Sugars and Polysaccharides

In essence, the same chemical change occurs when you burn a piece of wood or eat a piece of bread. Wood and bread are mixtures of carbohydrates, substances that provide energy through oxidation. 

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The Jordi polyamine column is a polar column for simple sugar and polysaccharide applications. The amine groups are bonded to the DVB backbone and are stable in aqueous mobile phases. This material does not self-hydrolyze as do many silica-based amino packings (Fig. 13.14). 

To gain an insight into the likely hydrolytic behavior of sulfated simple sugars and polysaccharides, Brimacombe, Foster, Hancock, Overend, and Stacey carried out a rigorous set of experiments with the cyclic sulfates of cyclohexane cis-and trims-1,2-diol as model compounds. The results were interpreted on the reasonable assumption that, in all cases, the cyclic sulfates initially afford a diol monosulfate. Examples of both S-0 and C-0 bond cleavage were encountered. A qualitative reaction mechanism was proposed for use as a working hypothesis for the hydrolysis of sugar sulfates. 

A recent study extensively investigated the pyrolysis of polysaccharide binders, with and without a silylating agent [56]. Some of the main results relative to the pyrolysis silylation of sugars and polysaccharide binders can be summarised as follows [56 59] ... 

Carbohydrates are characterized by the presence of polyhydroxylic aldehyde or polyhydroxy-lic ketone structures or polymers made of such units. Sugars and polysaccharides have definite... 

Sutton, R. B. Critical cooling rates for aqueous cryoprotectants in the presence of sugars and polysaccharides. Cryobiology 29, p. 585-598, 1992 Copyright 1992, Academic Press. Inc. 

Acetal and ketal linkages are widely foimd in nat-inal sugars and polysaccharides. The structure of sucrose is a splendid example. Sucrose is a disaccharide, composed of two linked monosaccharide imits, glncose in pyranose ring form and frnctose in fmanose ring form. As we have seen above,... 

The chapters of Part I are devoted to the structure and function of the major classes of cellular constituents water (Chapter 2), amino acids and proteins (Chapters 3 through 6), sugars and polysaccharides (Chapter 7), nucleotides and nucleic acids (Chapter 8), fatty acids and lipids (Chapter 10), and, finally, membranes and membrane signaling proteins (Chapters 11 and 12). We supplement this discourse on molecules with information about the technologies used to study them. Some of the techniques sections are woven throughout the molecular descriptions, although one entire chapter (Chapter 9) is devoted to an integrated... 

Now let us consider the further conversion of PEP and of the triose phosphates to glucose 1-phosphate, the key intermediate in biosynthesis of other sugars and polysaccharides. The conversion of PEP to glucose 1-P represents a reversal of part of the glycolysis sequence. It is convenient to discuss this along with gluconeogenesis, the reversal of the complete glycolysis sequence from lactic acid. This is an essential part of the Cori cycle (Section F) in our own bodies, and the same process may be used to convert pyruvate derived from deamination of alanine or serine (Chapter 24) into carbohydrates. 

Carbohydrates characteristically absorb volatile substances from the environment, and they also retain their volatility, even under drying cycles. Flavorisls have taken advantage of these properties, purposely using sugars and polysaccharides as flavor carriers." which is of particular interest in muking stable, dry. and llowuble Davor powders. 

The structures of sugars and polysaccharides are covered in the appropriate chapters within part 4 just prior to discussing their metabolism. Similarly, the structures of lipids are presented in the lipid metabolism chapters found in part 5. Nucleotide structures are addressed in chapter 23 before considering their metabolism. Finally, nucleic acid and nucleoprotein structures are examined in the first chapter (chapter 25) of part 7 prior to the discussion of the roles these molecules play in nucleic acid and protein metabolism in the six subsequent chapter. ... 

The most widely recognized method of selective etherification of sugars and polysaccharides involves the reaction of primary alcohol groups with triphenylmethyl (trityl) chloride. Helferich60 has described the selective character of this reagent, whose rate of reaction with primary hydroxyl groups is many fold that with secondary groups. 

One of the very important applications of the methyl ethers of sugars and polysaccharides has been in structure determination and for this purpose the complete substitution of all free hydroxyl groups of a given substance is required. Bourne and Peat61 have provided a full description of the principles, reagents, and conditions that are involved. 

Carbohydrates are characterized by the presence of polyhydroxylic aldehyde or poly-hydroxylic ketone structures or polymers of such units. Sugars and polysaccharides have definite three-dimensional structures that are important for many biological functions. They are hydrophilic and thus easily accessible to aqueous reaction mediums. The chemistry of bioconjugation using carbohydrate molecules begins with an understanding of the building blocks of polysaccharide molecules. 

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