Disaccharides trehalose

Fischer performed a few experiments with the natural disaccharide trehalose. It does not react with phenylhydrazine. A diastase from. green malt has no action on it Froliberg yeast has a weak action (1895). Carp blood hydrolyzes it rapidly, in contrast to the blood of other fishes. Extracts of the mucous membrane from the small intestines of horses and cattle are also active (1906). A. Kalanther, in Fischer s laboratory, found, in 1898. that wine yeasts also hydrolyze this disaccharide. 

Paiva C, Panek A (1996) Biotechnological applications of the disaccharide trehalose. Biotechnol Annu Rev 2 293... 

An interesting illustration of the roles played by low-molecular-mass protein stabilizers in assisting cells to cope with heat stress is provided by work of Singer and Lindquist (1998a,b), who examined the complementary roles of the disaccharide trehalose and heat-shock proteins in recovery from thermal stress by the yeast Saccharomyces cerevisiae. Many types of yeast produce high concentrations of... 

An interesting example of anhydrobiosis is a trandgrade which appears to utilize the disaccharide trehalose for water regeneration [718]. 

Deduce the structure of the disaccharide trehalose from the following data. Trehalose is the blood sugar of the insect world. It is found in bacterial spores, fungi, and many insects whose natural environment has large variations in temperature. 

Third, Carpenter et al. [36] recently documented more rigorously that freezing-induced denaturation can play an important role in the overall damage to a protein during lyophilization. The impetus for this research was the observation that the disaccharide trehalose was effective at protecting labile enzymes, whereas the constituent monosaccharide, glucose, was not. For example, when PFK is freeze-dried in the presence of 0.2-0.4 M trehalose, over 60% of the initial activ-... 

It often occurs that collisional spectra may eliminate stereochemical ambiguities. As an example, the disaccharide linkage in a free molecule may be determined by analyzing B/E/CAD spectra of molecular ions produced by field desorption [235]. The disaccharides trehalose (1 1), sophorose (1 - 2), nigerose (1 3), cellobiose (1 -+ 4)... 

The disaccharide trehalose, shown next, is the major reason why some plants and animals can withstand prolonged periods of dessication (severe dehydration). It is widely used in cosmetics and commercial foods, because of its high water retention properties. Is it a reducing or nonreducing disaccharide ... 

Fungi have characteristic soluble carbohydrates (the disaccharide trehalose and polyhydric alcohols like mannitol and arabitol) and storage compounds (e.g. glycogen), differing from those of most plants and animals. 

An important example of a carbohydrate ester is the so-called cord factor from Mycobacteria spp. This contains an ester of the disaccharide, trehalose, with two molecules of a complex acid, mycolic acid. The latter is a general term embracing a whole series of fatty acids containing 60-90 carbons. They are hydroxy fatty acids which differ in their degree of unsaturation and chain branching (Section 1.9). In the example given in Fig. 2.6 the mycolic acid is the 60-carbon compound found in Mycobacterium smeg-matis. 

The attachment of phosphines to carbohydrate residues can give not only recyclable but also enantioselective catalysts, in which chirality transfer occurs not from the phosphine part but from the carbohydrate. An example of such a ligand—the disaccharide trehalose modified with two diphenylphosphine residues to give a bidentate phosphine— has been published, though so far it has been used only for Rh-catalyzed recyclable enantioselective hydrogenation. This approach may be fruitful if tested for palladium catalysis. 

The disaccharide trehalose found in mushrooms is composed of two a-D-glucose molecules joined by an a,a-l,l-glycosidic bond. Draw the Haworth structure for trehalose. (18.1,18.2)... 

FIG. 25 Gemini surfactants (LXXVI, LXXVII) with a disaccharide trehalose as a polar spacer and catanionic geminis (LXXXVIII). 

In the field of non-reducing disaccharides trehalose has been converted into the hexabenzoate having free hydroxyl groups at both 4-positions and thereby, by... 

Hydrolysis of the disaccharide trehalose yields only D-glucose. Methylation of trehalose using dimethyl sulfate followed by mild acid hydrolysis yields 2,3>6-tri-0-methyl-D-glucose and 2,3,4,6-tetra-O-methyl-D-glucose. What features of the structure are determined by these data ... 

The syntheses of a modified carbohydrate moiety, a head-to-tail dimer of the calicheamicin oligosaccharide [176], the 1,1 -disaccharide (trehalose) containing the carbohydrate moiety of everninomycin [177], and the vancomycin disaccharide... 

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