Sugar constituents

Figure 1.40 The two forms of sugar residues commonly found in nucleic acids. 3-D-Ribose is the sugar constituent of RNA, while p-D-2-deoxyribose is a component of DNA.

Since sialic acid is a frequent terminal sugar constituent of the polysaccharide trees on glycoproteins, this method selectively forms reactive aldehydes on the most accessible parts for subsequent modifications. The carbohydrate polymer of a protein provides a long spacer arm that can be used to conjugate another large macromolecule, such as a second protein, with little steric problems. 

Polysaccharides that are formed from only one type of monosaccharide are called homo-glycans, while those formed from different sugar constituents are called heteroglycans. Both forms can exist as either linear or branched chains. 

J. Thiem and D. Springer, Synthesis and hydrogenation studies of 3-azidohex-2-enopyranosides, precursors of the sugar constituents of anthracycline glycosides, Carbohydr. Res., 136 (1985) 325-334. 

South Africa.64 The average composition of 490 samples of honey, with respect to sugar constituents and moisture and their range of values, as determined by White and collaborators,45 is given in Table I. The values given in Table I for maltose and sucrose do not... 

Nectar studies included an analysis of constituents, a study of daily secretion patterns, and also total volumes produced per flower. Calibrated micropipettes were inserted into the pool of nectar that accumulates at the base of the corolla tube, with nectar extracted by capillary action. Sugar concentrations were measured with an Extech model 2132 pocket refractometer, with several nectar samples also analyzed for sugar constituents (ratio) by Irene Baker at UC Berkeley. 

Baker, H.G., and I. Baker. 1983. Floral nectar sugar constituents in relation to pollinator type. In, C.E. Jones and R.J. Little, eds.. Handbook of experimental pollination biology. Scientific and Academic Editions. New York. 

O-Chains (and core structures) contain many unique or unusual sugar constituents and, in recent years, many members of different sugar classes have been identified in lipopolysaccharides (Table I). 

Fig. 21. Sugar constituents of animal ycoproteins. N—Acetylneuraminic acid is shown as an example of the sialic acids. From Spiro (S34).

Aminoglycal derivatives are of special interest in connection with the synthesis of sugar constituents of antibiotics [164], and their preparation is covered above inO Sect 6. However, reactions of hex-2-enop)ranosides with chlorosulfonyl isocyanate [214,215], which involve double bond migration, (113 to 114), should also be mentioned since they are one-step procedures of considerable synthetic potential (O Scheme 38). 

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