Lipase-catalyzed transesterification in organic media: solvent effects on equilibrium and individual rate constants. - INSA Toulouse - Institut National des Sciences Appliquées de Toulouse Access content directly
Journal Articles Biotechnology and Bioengineering Year : 1998

Lipase-catalyzed transesterification in organic media: solvent effects on equilibrium and individual rate constants.

L García-Alles
V Gotor
  • Function : Author

Abstract

The kinetics of the immobilized lipase B from Candida antarctica have been studied in organic solvents. This enzyme has been shown to be slightly affected by the water content of the organic media, and it does not seem to be subject to mass transfer limitations. On the other hand, some evidence indicates that the catalytic mechanism of reactions catalyzed by this lipase proceeds through the acyl-enzyme intermediate. Moreover, despite the fact that the immobilization support dramatically enhances the catalytic power of the enzyme, it does not interfere with the intrinsic solvent effect. Consequently, this enzyme preparation becomes optimum for studying the role played by the organic solvent in catalysis. To this end, we have measured the acylation and deacylation individual rate constants, and the binding equilibrium constant for the ester, in several organic environments. Data obtained show that the major effect of the organic solvent is on substrate binding, and that the catalytic steps are almost unaffected by the solvent, indicating the desolvation of the transition state. However, the strong decrease in binding for hydrophilic solvents such as THF and dioxane, compared to the rest of solvents, cannot be easily explained by means of thermodynamic arguments (desolvation of the ester substrate). For this reason, data have been considered as an indication of the existence of an unknown step in the catalytic pathway occurring prior to formation of the acyl-enzyme intermediate.
No file

Dates and versions

hal-03367179 , version 1 (06-10-2021)

Identifiers

  • HAL Id : hal-03367179 , version 1
  • PUBMED : 10099389

Cite

L García-Alles, V Gotor. Lipase-catalyzed transesterification in organic media: solvent effects on equilibrium and individual rate constants.. Biotechnology and Bioengineering, 1998, 59 (6), pp.684-94. ⟨hal-03367179⟩

Collections

INSA-TOULOUSE
7 View
0 Download

Altmetric

Share

Gmail Mastodon Facebook X LinkedIn More