Anomerization of Furanose Sugars and Sugar Phosphates
Thermodynamic and kinetic parameters for the ring-opening and -closing reactions of several aldo- and ketofuanoses and their phosphate esters have been determined by NMR line-width and saturation-transfer methods.Cyclic forms interconvert via a single, acyclic carbonyl form under either acid or base catalysis.Ring-opening rates do not correlate with thermodynamic stability of the rings.For aldofuranose phosphates, α anomers open faster than β anomers; for ketofuranose phosphates the converse is observed.Intramolecular catalysis of anomerization by the phosphate group of sugar phosphates is documented.Biological and mechanistic implications of the observed kinetics are discussed.
Pierce, John,Serianni, Anthony S.,Barker, Robert
p. 2448 - 2456
(2007/10/02)
Synthesis of Sugars by Aldolase-Catalyzed Condensation Reactions
Dihydroxyacetone phosphate was prepared in 200-mmol scale from dihydroxyacetone by two procedures: reaction with phosphorus oxytrichloride and glycerol kinase catalyzed phosphorylation using ATP with in situ regeneration of ATP by phosphoenolpyruvate or acetyl phosphate.Dihydroxyacetone phosphate was converted to fructose 6-phosphate in 80percent yield by exposure to a mixture of co-immobilized triosephosphate isomerase and aldolase followed by acid hydrolysis of the condensation product fructose 1,6-bisphosphate.Fructose 6-phosphate was subsequently converted by chemical and enzymatic schemes into fructose, glucose 6-phosphate, and glucose.Practical procedures are described for the preparation of D- and L-glyceraldehyde 3-phosphate and for several hexoses labeled with 13C in the C-2 and C-2,5 positions.
Wong, Chi-Huey,Whitesides, George M.
p. 3199 - 3205
(2007/10/02)
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