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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
3
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pubmed:dateCreated |
1985-11-25
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pubmed:abstractText |
The thermodynamics of the equilibria between aqueous ribose, ribulose, and arabinose were investigated using high-pressure liquid chromatography and microcalorimetry. The reactions were carried out in aqueous phosphate buffer over the pH range 6.8-7.4 and over the temperature range 313.15-343.75 K using solubilized glucose isomerase with either Mg(NO3)2 or MgSO4 as cofactors. The equilibrium constants (K) and the standard state Gibbs energy (delta G degrees) and enthalpy (delta H degrees) changes at 298.15 K for the three equilibria investigated were found to be: ribose(aq) = ribulose(aq) K = 0.317, delta G degrees = 2.85 +/- 0.14 kJ mol-1, delta H degrees = 11.0 +/- 1.5 kJ mol-1; ribose(aq) = arabinose(aq) K = 4.00, delta G degrees = -3.44 +/- 0.30 kJ mol-1, delta H degrees = -9.8 +/- 3.0 kJ mol-1; ribulose(aq) = arabinose(aq) K = 12.6, delta G degrees = -6.29 +/- 0.34 kJ mol-1, delta H degrees = -20.75 +/- 3.4 kJ mol-1. Information on rates of the above reactions was also obtained. The temperature dependencies of the equilibrium constants are conveniently expressed as R in K = -delta G degrees 298.15/298.15 + delta H degrees 298.15[(1/298.15)-(1/T)] where R is the gas constant (8.31441 J mol-1 K-1) and T the thermodynamic temperature.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Aldose-Ketose Isomerases,
http://linkedlifedata.com/resource/pubmed/chemical/Arabinose,
http://linkedlifedata.com/resource/pubmed/chemical/Carbohydrate Epimerases,
http://linkedlifedata.com/resource/pubmed/chemical/Pentoses,
http://linkedlifedata.com/resource/pubmed/chemical/Ribose,
http://linkedlifedata.com/resource/pubmed/chemical/Solutions,
http://linkedlifedata.com/resource/pubmed/chemical/ribulose,
http://linkedlifedata.com/resource/pubmed/chemical/xylose isomerase
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pubmed:status |
MEDLINE
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pubmed:month |
Aug
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pubmed:issn |
0301-4622
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
22
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
197-204
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pubmed:dateRevised |
2011-11-17
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pubmed:meshHeading |
pubmed-meshheading:3931718-Aldose-Ketose Isomerases,
pubmed-meshheading:3931718-Arabinose,
pubmed-meshheading:3931718-Carbohydrate Epimerases,
pubmed-meshheading:3931718-Kinetics,
pubmed-meshheading:3931718-Pentoses,
pubmed-meshheading:3931718-Ribose,
pubmed-meshheading:3931718-Solutions,
pubmed-meshheading:3931718-Streptomyces,
pubmed-meshheading:3931718-Thermodynamics
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pubmed:year |
1985
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pubmed:articleTitle |
An investigation of the equilibria between aqueous ribose, ribulose, and arabinose.
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pubmed:publicationType |
Journal Article
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