Sugar nucleotide-modifying enzymes

Sugar nucleotides serve as the activated forms of carbohydrates that are used in a wide range of biosynthetic pathways. Instead of building up the sugar nucleotide from the free sugar itself, nature often chooses to modify the "donor" portion of a pre-existing sugar nucleotide in a biosynthetically efficient manner. In doing so a rich variety of catalytic strategies are employed and this review focuses on recent mechanistic and structural studies of the sugar nucleotide-modifying enzymes. The review is organized around the types of reactions catalyzed and contains the following sections: Epimerases/Mutases/Decarboxylases, Eliminations and Substitutions, Oxidation and Reduction, and Substitutions on the Periphery of Sugar Nucleotides.