title: Thermodynamics of carbohydrate isomerization reactions. The conversion of aqueous allose to psicose.
abstract: The thermodynamics of the conversion of aqueous D-psicose to D-allose has been investigated using high-pressure liquid chromatography. The reaction was carried out in phosphate buffer at pH 7.4 over the temperature range 317.25-349.25 K. The following results are obtained for the conversion process at 298.15 K: DeltaG degrees = - 1.41 +/- 0.09 kJ mol(-1), DeltaH degrees = 7.42 +/- 1.7 kJ mol(-1), and DeltaC(p) degrees = 67 +/- 50 J mol(-1) K(-1). An approximate equilibrium constant of 0.30 is obtained at 333.15 K for the conversion of aqueous D-psicose to D-altrose. Available thermodynamic data for isomerization reactions involving aldohexoses and aldopentoses are summarized.
authors.affiliation: Chemical Thermodynamics Division, Center for Chemical Physics, National Bureau of Standards, Gaithersburg, MD 20899, U.S.A.
authors.forename: Y B
authors.initials: YB
authors.lastname: Tewari
authors.forename: R N
authors.initials: RN
authors.lastname: Goldberg