Structure from sucrose

The action of j8-D-fructofuranosidase from Candida utilis on various derivatives of sucrose (1) and methyl j8-D-fructofuranoside (2), as well as on compounds with related structures has been examined.None of the compounds in Table 1 was hydrolysed by the enzyme, even though many of them are only slightly different structurally from sucrose or methyl S-D-fructofuranoside. It is clear that minor changes at the 1 -, 4 -, or 6 -position cause loss of substrate capability, and it was concluded that ]8-D-fructofuranosidase from Candida utilis is a highly specific enzyme. 

Structure of the Dextran Synthesised from Sucrose by a New Strain of Betacoccus arabinosa-ceous" M. Stacey and G. Swift, J. Chem. Soc., (1948) 1555-1559. 

The Structure of the Starch-like Polysaccharide Synthesised from Sucrose by Neisseria perflava" S. A. Barker, E. J. Bourne, and M. Stacey,/. Chem. Soc., (1950) 2884- 2887. 

Whereas humans can obtain energy from sucrose, insects obtain energy from trehalose, whose line structure follows. Identify the monosaccharides from which trehalose is constructed. 

Dextran is produced from sucrose by a number of bacteria the major ones being the nonpathogenic bacteria Leuconostoc mesenterodes and Leuconostoc dextranicum. As expected, the structure (and consequently the properties) of the dextran is determined by the particular strain that produces it. 

The levan synthesized by B. subtilis from raffinose was shown by Mitchell and Hibbert100 to be identical in structure with that obtained from sucrose. 

Other levans produced by widely different organisms all have similar structures, e. g., the levans1020 produced from sucrose by B. megatherium, Phytomonas pruni and P. prunicola, and those1020 produced from sucrose... 

The nitrogen-containing carbon replicas of MLV-0.75 exhibit a poorer structure ordering as compared to the carbons obtained from sucrose. It is in contrast to the CMK-3 samples as replicas of SBA-15. The OCM carbons contain up to 6.5% N whereas CMK-3, up to 5%. Probably, the removal of nitrogen during carbonisation proceeds from hexagonal structures easier than from onion-like ones. In the OCM samples, the amount of the used FeCh determines their structure ordering. 

The spiroacetal morpholine work of Scheme 38 subsequently inspired research on the preparation of a novel family of morpholino-glycosides from sucrose via lead tetraacetate cleavage and reductive amination (Scheme 40). Significantly, the latter work, which was done with the present author, unveiled a completely new structural class of sweeteners, more intense than sucrose but having a similar taste profile. 

No-calories fat substitutes, such as sucrose polyesters (Olestra), which are synthesized from sucrose and fatty acid methyl esters, have been widely studied and several snacks fried in this medium are available in the market place. This product has no calories since digestive enzymes are not able to break it down due to structural impairment. A major disadvantage that prevents a wide acceptance of this product is related to the gastrointestinal discomfort that may be caused to some individuals (Dobraszczyk et ah, 2006, p. 104). 

Problem 22.39 (u) Give the structure of sucrose (cane and beet sugar) from the following information (1) It is hydrolyzed by maltase or emulsin to a mixture of d-( )-glucose and D-(-)-fructose. (2) It does not reduce Fehling s solution and does not mutarotate. (3) Methylation and hydrolysis gives 2,3,4.6-tetra-O-methyl-D-glucose and a tetramethyl-D-fructose. (b) What structural features are uncertain ... 

Fig. 1. Structural representations of sucrose (a) Haworth perspective formula, and (b) conformational structure of sucrose in solid crystals. Adapted from...

A final example is the work of Wolfram and Shafizadeh1 8 on the structure of sucrose, for which Hudson had given an a-D configuration for the o-glucopyranosyl moiety, based on the results of invertase-catalyzed hydrolysis. These workers,128 using data from the methyl n-fructofuranosides, demonstrated that this hydrolysis is not accompanied by a Walden inversion and that the original work of Hudson was correct. 

Considering these problems, we tested a computer extrapolation (6) for sucrose, shown in the conformation maps in Figure 4. Four sets of crystal parameters were used, those from the structure of sucrose (S) (45) and those from the sucrose component of raffinose pentahydrate... 

Sucralose, Developed in England during the mid-1980s, testing and evaluation commenced in 1988. The structural formula of the compound (a chlorinated disaccharide derived from sucrose) is shown below. 

FIG. 1.—Structural representation of segments of different glucans synthesized by glucansucrases from sucrose. 

As has been described, the combined use of two phosphorylases is a powerful tool to convert one carbohydrate into another with a different structure. The idea of phosphorylase coupling was first examined by Waldmann et al. (1986), but had been employed for the synthesis of cellobiose from sucrose (Kitaoka et al., 1992), laminaribiose from sucrose (Kitaoka et al., 1993), trehalose from maltose (Yoshida et al., 1995) and kojioligosaccharides from trehalose (Chaen et al., 1999). Discovery of new phosphorylases and their application through phosphorylase coupling should be a promising area in polysaccharide and carbohydrate engineering. 

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