A, 3-Trehalose

For the disaccharide to be nonreducing, the anomeric carbons of both glucose molecules must be linked via a glycosidic bond. The product is called trehalose, and it exists in three isomeric forms in which the glucose molecules are linked a,a /3,/3 or ar,/3 (shown), a,/3-Trehalose is a-o-glucopyranosyl-(l — l)-/3-D-gl ucopy ranose. 

Haworth and Hickinbottom prepared 1 g. of a, 3-trehalose hepta-acetate from 5.2 g. of Brigl s anhydride (3,4,6-tri-O-acetyl-l, 2-anhydro-a-D-glucopyranose) and 9.2 g. of 2,3,4,6-tetra-0-acetyl-/3-D-glucose. The mixture was covered with benzene and kept at 90-100° for 37 hours, moisture being excluded. 

There was better agreement with calculations made on the basis of Klyne s rules, except for ,a-trehalose octaacetate. It was assumed that both parts of the trehalose molecule are identical. Moreover, the calculated values agreed more closely with the less positive values reported for a,/3-trehalose octaacetate (see Tables VII and VIII). 

Trehalose, a disaccharide produced in fungi, has the following structure ... 

Similar instances, in which analytical data were of prime importance and where no products were isolated, are the oxidations of various di-D-fructose dianhydrides,80 inositols,81 the trisaccharide moiety of the alkaloid solamargine,82 2-O-a-L-fucopyranosyl-L-fucitol derived from fucoidin83 (a polysaccharide sulfate ester), trehalose and neotrehalose,84 maltotetraose,85 D-galactopyranosyl-glyceritol,86 and a 3-pentulose.87... 

Crowe and Crowe [3.39] proved that it is sufficient for certain liposomes, e. g. egg phosphatidyl-choline (DPPC), to be vitrified by trehalose or dextran during freezing and freeze drying. In trehalose the retention rate was almost 100 %, and in dextran more than 80 %. This did not apply to egg PC-liposomes Dextran as CPA alone led to an almost total loss of the CF-indicator, but addition of dextran into a trehalose solution (Fig. 3.20) also reduced the retention rate of CF substantially, e. g. from 90 % in a pure trehalose to approx. 45 % if trehalose and dextran were in equal amounts in the solution. Since T of dextran is approx. -10 °C and Tg- of trehalose is -30 to -32 °C, dextran should form a glass phase at much higher temperatures than trehalose. Therefore the stabilization of egg- PC with trehalose cannot be related with the vitrification. Crowe showd with IR spectroscopy that egg-PC freeze dried with 2 g trehalose/g lipid had almost the identical spectrographic characteristics as the hydrous lipid Trehalose molecules replaced the water molecules, and hydrogen... 

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