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Monosaccharides structurally modified

Monosaccharides with modified structures are often biologically important. Examples include sugar phosphates, deoxy sugars, amino sugars, and ascorbic acid (vitamin C). [Pg.292]

In many cases the monosaccharides found in these complex structures are present as one of their chemical derivatives, which may be an oxidation or reduction product, a phosphate or sulphate ester or an amino derivative, etc. However, these modified forms of monosaccharides may themselves have important biochemical roles and are not always found incorporated in polysaccharides. [Pg.315]

Preparation of modified, bacterial polysaccharides having monosaccharide analogs inserted into the polymeric chain is of interest for study of the structure-properties relationship in these biopolymers. Incorporation of chemically prepared, modified, biosynthetic precursors of the polymers in enzymic reactions seems a promising approach for achieving this aim. Such an approach, which may be termed chemical-enzymic synthesis, has now been studied by our group,439-441 using O-specific polysaccharides (10-12) of Salmonella serogroups B and E as an example. [Pg.335]

The IUPAC-IUBMB short form symbolism18 2-Carb-38.5 is used here and elsewhere in this chapter for designation of oligosaccharide structures. Parent monosaccharide residues are the d enantiomers except for IdoA, which is the l enantiomer. Uronic acid residues modified by 44-unsaturation are prefixed by A4tS, and the associated anomeric symbol relates to the configuration at the 5-position of that residue before 4,5-elimination. The abbreviation HexA is used to denote either d-G1cA or L-IdoA. [Pg.202]

One of the primary dividends resulting from this disconnection was its exposure of a possible relationship between the target and a monosaccharide precursor. After systematic analysis, Pearson saw that the stereochemistry of 5 correlated perfectly with lactone 7. Furthermore, lactone 7 had a structure appropriate for easy synthetic elaboration into 6 since it was functionally differentiated at C(l) and C(4). It therefore appeared fully capable of being selectively modified in the manner required to obtain 5. [Pg.288]

The configurations of monosaccharides are described by several types of formulas. As an example, the following formulas are shown for a-D-glucopyranose structural, Haworth, modified Fischer, and Fischer. In Fischer formulas the -H or -OH groups are above or below the plane formed by the hemiacetal bonds and the carbon chain (-H bonds are shown shorter). [Pg.218]

As the accompanying structure shows, the carbohydrate portion of the peptidoglycan is a polymer of alternating units of two modified glucose molecules called N-acetylglucosamine and N-acetylmuramk acid. These two unusual monosaccharides... [Pg.510]


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See also in sourсe #XX -- [ Pg.16 , Pg.17 , Pg.18 , Pg.19 , Pg.20 ]




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