Sugar Nucleotides UDPG

Reflect and Apply Suggest a reason why sugar nucleotides, such as UDPG, play a role in glycogen synthesis, rather than sugar phosphates, such as glucose-6-phosphate. 

In general, these compounds are derived via UDP-glucose (UDPG) or a similar sugar nucleotide (Fig. 15.15). In gen-... 

We have established a new aspect in nucleotide sugar synthesis by the application of sucrose synthase (UDPG D-fructose 2 glucosyltransferase, EC 2.4.1.13) the use of sucrose as a renewable resource for nucleotide sugar synthesis [273]. 

Pyrophosphate Uridyl Transferase. The over-all epimerase reaction is composed of three individual reactions. The sugar phosphates are not converted directly into each other, but are first incorporated into uridine nucleotides. Epimerization occurs in the hexose component of the UDP-sugar, which then is cleaved to yield the epimerized sugar phosphate. The synthesis of both UDPG and the corresponding galactose derivative, UDPGal, are catalyzed by enzymes called uridyl transferases. A pyrophosphate (PP) uridyl transferase has been studied in yeast and in several mammalian tissues. It catalyzes the reaction... 

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