Monosaccharides characterization

An important characterization parameter for ceUulose ethers, in addition to the chemical nature of the substituent, is the extent of substitution. As the Haworth representation of the ceUulose polymer shows, it is a linear, unbranched polysaccharide composed of glucopyranose (anhydroglucose) monosaccharide units linked through thek 1,4 positions by the P anomeric configuration. 

Carbohydrates are major constiments of animal food and animal tissues. They are characterized by the type and number of monosaccharide residues in their molecules. 

Monosaccharides are probably involved in the browning reactions that occur during the roasting of coffee. Caramelization involving the sugars alone, and Maillard reactions, between sugars and free amino acids, produce polymeric yellow to dark brown substances, known as melanoidins. These melanoidins can be extracted into hot water, separated and characterized.105... 

A classical, and still most useful, physicochemical parameter for characterizing glycosaminoglycans is their specific optical rotation. For pure heparins from common sources, [a]80 = + 45 to + 53 ° (see Table II). The actual value depends on the relative proportions of monosaccharide constituents (that is, the L-idosyluronic acid residues make a less positive contribution than the n-glucosyluronic residues), and on the degree of sulfation of the preparation (that is, although sulfate groups may have little direct influence on the molecular rotation, they lower the value by acting as diluents ). 

Dermatan sulfate, also termed chondroitin sulfate B, a related glycosaminoglycan constituent of connective tissue, was known to be composed of galactosamine and a uronic acid, originally believed to be glucuronic acid but then claimed to be iduronic acid based largely on color reactions and paper chromatography. However, the d or L-enantiomer status of the latter monosaccharide was not clear. Jeanloz and Stoffyn unequivocally characterized the monosaccharide as L-iduronic acid by consecutive desulfation, reduction, and hydrolysis of the polysaccharide, followed by isolation of the crystalline 2,3,4-tri-0-acetyl-l,6-anhydro-/ -L-idopyranose, which was shown to be identical to an authentic specimen synthesized from 1,2-0-isopropylidene-/ -L-idofuranose.34... 

Sialic acids are nine-carbon monosaccharides involved in a wide range of biological phenomena. Their unique structure is characterized by the presence of a carboxylic... 

The next chapter, by Ren Csuk and Brigitte I. Glanzer (Zdrich), constitutes an extensive treatise on the nuclear magnetic resonance (n.m.r.) spectroscopy of fluorinated monosaccharides [whose early chemistry was surveyed in Vol. 38 (1981) by Anna A. E. Penglis] the comprehensive data tabulated herein should be especially of value to those working in the fleld. It continues the coverage, in Advances, of n.m.r. spectroscopy as the key tool for characterization of carbohydrates. It complements articles on the H-n.m.r. spectroscopy of carbohydrates by Laurance D. Hall [Vols. 19 (1964) and 29 (1974)], Bruce Coxon [Vol. 27 (1972)], and Johannes F. G. Vliegenthart, Lambertus Dorland, and Herman van Halbeek [Vol. 41 (1983)], and on the C-n.m.r. spectroscopy of monosaccharides by Klaus Bock and Christian Pedersen [Vol. 41... 

The lysosomal disorder SASD is characterized by accumulation of the free acid monosaccharide sialic acid in the lysosomal compartment of the cell. Diagnosis is based on the demonstration of abnormal excretion of free, not OGS-bound sialic acid in urine, coupled with accumulation of free sialic acid in cultured fibroblasts, and on microscopic evidence of vacuoles (increased and swollen lysosomes filled with light electron-lucent material in skin biopsy and peripheral blood lymphocytes). The inheritance is autosomal recessive. There are different clinical forms of this disorder an adult form, called Salla disease (SD) or Finnish sialuria (OMIM 604369) infantile SASD (ISSD OMIM 269920) and an intermediate form, severe Salla disease [3,16]. 

Although FAB-MS gives information on the sequence of monosaccharides in the oligosaccharide moiety, it is not possible to determine the location of the interglycosidic linkages by this method. NMR has been the method of choice for complete characterization of the oligosaccharide chain. 

The mass spectra of the monosaccharides having a free hydroxyl group at C-l are characterized by a rather poor reproducibility of the relative intensities this must be due to the lower thermostability of these compounds compared with that of the 1-0-substituted derivatives. For this reason, analytical application to this type of compound does not seem very promising.84... 

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