Nucleotide sugar diphosphates NDPs

Fig. 4 Synthesis of nucleotide sugars from sucrose and nucleoside diphosphates (NDPs) by a sucrose synthase...

Starting from sucrose, one-pot reactions are suitable to work as regeneration cycles for nucleotide sugars as demonstrated for UDP-Glc, UDP-Gal, and dTDP-deoxy-sugars [98-103] (Scheme 6.4). Sucrose synthase (SuSy), known for the reverse reaction of a GT, is used in combination with different enzyme module systems. Nucleoside diphosphate (NDP) from GT modules are substrates of SuSy catalyzed synthesis of activated glucose (UDP-Glc, dTDP-Glc) which enter enzyme modules to generate the donor substrates of GTs. 

The condensed IUPAC-IUB system of terminology for sugar residues, oligosaccharide chains, and polysaccharides [Eur. J. Biochem., 126 (1982) 433-437, 439-441] is used in somewhat modified form in the present article. The abbreviations GIc, Gal, and Man stand for pyranoses of the d series, and Rha and Fuc for pyranoses of the l series, unless stated otherwise. The abbreviation NDP for nucleotides means nucleoside S -diphosphate, with nucleoside residues abbreviated as recommended by the IUPAC-IUB. 

The key intermediates in the biosynthesis of 6-deoxy sugars are the nucleoside 6-deoxyhexosyl-4-ulose diphosphates (7), formed through enzymic reactions catalyzed by NDP-sugar 4,6-dehydratases (EC 4.2.1.45-47) from primary glycosyl nucleotides. These reactions were observed... 

Nucleotides are also found in which two or three phosphate groups are linked together, the chain of phosphate groups bonded to the sugar s 5 -position. In these cases, they are nucleoside diphosphates (5 -NDP) and nucleoside triphosphates (5 -NTP). 

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