conditions. In principle, the developed methodology can be
transferred to a large number of different enzymes. However, the
determination of kinetic parameters as described here is only
applicable to enzymes which catalyse irreversible reactions.
Activity was high enough in 25 of the ionic liquids to allow
estimation of the Michaelis–Menten parameters. The enzyme
showed residual activity in a dozen further ionic liquids, but the
activity was either too low to estimate kinetic parameters or the
ionic liquids caused too much light scattering to allow accurate
determination of the rate. In the specific case of LTV, it could be
concluded that biphasic ionic liquid–water systems were more
suitable for the enzyme than solutions of water-miscible ionic
liquids. This is, perhaps, unsurprising, because any effects of
ions on the enzyme depends on their activity.
immiscible examples. These are now available for deployment in
laccase-catalysed processes for chemical synthesis and bioreme-
diation where substrate solubility restricts the efficiency of the
process.
Acknowledgements
This work was funded by a BBSRC Research Development
Fellowship to Gill Stephens, and by QUILL and the Technology
Strategy Board’s Collaborative Research and Development
programme.
Notes and references
The enzyme performance depended strongly on the nature of
the anion. [NTf2]− and [AOT]− proved to be the most suitable
anions for water-immiscible ionic liquids, and alkyl sulfates with
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important (and in ionic liquids, they are dominant), the extrapol-
ation to infinite dilution will be complex and certainly non-
linear.41 Perhaps, not surprisingly therefore, there are very
limited published data on viscosity B-coefficients of ionic
liquids, and nor are they mentioned in two very recent review of
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732 | Green Chem., 2012, 14, 725–733
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