Biosynthesis nucleotide sugars

Purine ribonucleotide biosynthesis Pyrimidine ribonucleotide biosynthesis Salvage of nucleosides and nucleotides Sugar-nucleotide biosynthesis and conversions Other... 

By the combination of C. ammmoniagenes and E, coli expressing the genes involved in sugar nucleotide biosynthesis, a large amount of sugar nucleotides could be accumulated in the reaction mixture. 

L. F. Leloir (Buenos Aires) discovery of sugar nucleotides and their role in the biosynthesis of carbohydrates. 

The type-specific capsular polysaccharide from Streptococcus pneumoniae type 5 contains 2-acetamido-2,6-dideoxy- -D-x>>/o-hexopyranosyl-4-ulose residues (17). Sugar nucleotides of hexos-4-uloses are important intermediates in the transformation of sugars during the biosynthesis, but this is the only known example of such a sugar as a polysaccharide component. 

The biosynthesis of Kdo and neuraminic acid is known to involve enol-pyruvate phosphate and D-arabinose or 2-acetamido-2-deoxy-D-mannose, respectively. Nothing is known about the biosynthesis of all the other glycu-losonic acids. One interesting problem is, for example, whether the two 5,7-diamino-3,5,7,9-tetradeoxynonulosonic acids are synthesized analogously to neuraminic acid, from a three- and a six-carbon fragment, by modification of neuraminic acid on the sugar nucleotide level, or by a third, less obvious route. 

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