| Autor: |
G. L. Lemière, T. A. van Osselaer, Frank C. Alderweireldt, J. A. Lepoivre |
| Rok vydání: |
2010 |
| Předmět: |
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| Zdroj: |
Bulletin des Sociétés Chimiques Belges. 89:133-149 |
| ISSN: |
0037-9646 |
| DOI: |
10.1002/bscb.19800890209 |
| Popis: |
Reaction rate constants for the catalytic step HLAD-NADH + ketone HLAD-NAD+ + alcohol in the HLAD-catalyzed reduction of 3-alkyl- and 4-alkylcyclohexanones are determined from initial rate measurements in the coenzyme recycling system ketone-ethanol-NAD+-HLAD. By rate measurements at several temperatures, activation parameters were determined and isokinetic relationships tracked down. Two different isokinetic relationships show that the 3-alkylcyclohexanones pass through an other type of transition state than cyclohexanone and the 4-alkylcyclohexanones, which means that they have a different arrangement on the HLAD-NADH complex. The results are rationalized in view of the most recent principles on nucleophilic additions to carbonyl functions. The resulting model for the HLAD-catalyzed reduction adequately explains the observed rate accelerating and decelerating effects and the stereochemistry of the reduction as well. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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