The temperature dependence of enzymatic kinetic resolutions reveals the relative contribution of enthalpy and entropy to enzymatic enantioselectivity
1999 (English)In: Biocatalysis and Biotransformation, ISSN 1024-2422, Vol. 17, no 1, 61-79 p.Article in journal (Refereed) Published
The temperature dependence of the enantioselectivity of several lipase-calalyzed hydrolysis and acylation reactions of racemic esters and alcohols has been determined. From the results we estimated the difference in activation enthalpy (Delta Delta H-# and activation entropy (Delta Delta S-#) for the two enantiomers in the enantioselective reaction step. Contrary to earlier suggestions, we found that the enthalpic and entropic contributions to the enantioselectivity are of similar magnitude. A plot of Delta Delta H-# versus Delta Delta S-#-values of data available in the literature for various enzyme-substrate combinations revealed a tempting correlation between the enthalpic and entropic contributions. This observation would imply enthalpy-entropy compensation to be a general feature of enantioselective enzymatic catalysis. On closer inspection of the data set it was realized that this trend must be considered fortuitous. It originates from the non-random collection of those enzyme-substrate combinations for which the numerical value of the enantiomeric ratio can be measured with a suitable degree of accuracy at ambient temperatures. Indications for the occurrence of genuine enthalpy-entropy compensation, however, have been observed for series of homologous substrates and changes of solvent composition.
Place, publisher, year, edition, pages
1999. Vol. 17, no 1, 61-79 p.
IdentifiersURN: urn:nbn:se:kth:diva-13386ISI: 000080165300006OAI: oai:DiVA.org:kth-13386DiVA: diva2:324820
QC 201006162010-06-162010-06-162010-06-16Bibliographically approved