title: Observations on the mechanism of the reversible epimerization of GDP-D-mannose to GDP-L-galactose by an enzyme from Chlorella pyrenoidosa.
abstract: An enzyme fraction from the green alga Chlorella pyrenoidosa that catalyzes the reversible epimerization of guanosine 5'-diphosphate D-mannose to guanosine 5'-diphosphate L-galactose brings about the incorporation of tritium from  tritium-labeled water into the hexosyl moieties of those sugar nucleotides. The hexoses were degraded by periodate oxidation whereby the tritium was found to be equally distributed between carbon atoms 3 and 5. That observation was taken to imply that the epimerizations proceed via ene-diol intermediates.
mesh_terms: D002238:Carbohydrate Epimerases / Q000378:metabolism*; D002708:Chlorella / Q000201:enzymology*; D005690:Galactose; D006155:Guanosine Diphosphate Mannose; D006156:Guanosine Diphosphate Sugars; D009702:Nucleoside Diphosphate Sugars; D010084:Oxidation-Reduction; D010504:Periodic Acid
chemical_list: D006156:Guanosine Diphosphate Sugars; D009702:Nucleoside Diphosphate Sugars; D010504:Periodic Acid; D006155:Guanosine Diphosphate Mannose; D002238:Carbohydrate Epimerases; D005690:Galactose