Uridine diphosphate glucose-fructose

Stoichiometric quantities of uridine diphosphate glucose were used, in the presence of a transfer enzyme, sucrose synthetase, in the soluble state (extraction given). Coupling with modified D-fructose gave sucroses modified on the D-fructosyl group, on the 1 -3-mmol scale. Thus were prepared l -deoxy-l -fluoro- (59%),98 4 -deoxy-4 -fluoro- (16%), and l -azido-l -deoxy-sucrose (15%).71 6-Deoxy-6-fluoro-D-glucose was isomerized to 6-deoxy-6-fluoro-D-fructose with isomerase, and gave 6 -deoxy-6 -fluoro-sucrose.71... 

FIGURE 10.20 The action of fructan 1-exohydrolase and fructan fructan 1-fructosyltransferase in dormant and sprouting tubers on inulin depolymerization. Abbreviations 1-feh = fructan 1-exohydrolase 1-fft = fructan fructan 1-fructosyltransferase hk = hexokinase spp = sucrose phosphate phosphatase sps = sucrose phosphate synthase GF = sucrose G = glucose F = fructose GFF = 1-ketose GF-P = sucrose phosphate UDP-G = uridine diphosphate glucose F-6-P = fructose-6-phosphate. 

Figure 20.13. Synthesis of Sucrose. Sucrose 6-phosphate is formed by the reaction between fructose 6-phosphate and the activated intermediate uridine diphosphate glucose (UDP-glucose).

Abbreviations used Gal-l-P, galactose-l-phosphate UDPG, uridine diphosphate glucose G-l-P, glucose-l-phosphate G-6-P, glucose-6-phosphate F-6-P, fructose-6-phosphate F-l,6-P, fructose-1,6-diphosphate G-3-P, glyceraldehyde-3-phosphate DHAP, dihydroxyacetone phosphate F-l-P, fructose-1-phosphate PG, 6-phospho-gluconic acid R-5-P, ribulose-5-phosphate S-7-P, sedoheptulose-7-phosphate. 

Sucrose synthase (SuSy) provides another potential pathway for eontrolling cellulose production. SuSy cleaves sucrose in the presence of uridine diphosphate (UDP) into UDP-glucose and fructose, thereby conserving the energy of the glycosidic bond ... 

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