Hofmeister effects: an explanation for the impact of ionic liquids on biocatalysis

Ionic liquids (ILs) have shown potentials as a new reaction medium for biocatalysis, either as such or as mixture. Their unique ionic nature is important in affecting the enzyme performance, and effects provide a reasonable explanation for this. In this review, the impact of Hofmeister on enzyme performance in aqueous solution was first examined, concerning the specific ion effects the bulk water properties, modifying the protein-water interactions, and interacting with the molecules: then the effect of IL cations and anions on enzyme activity and stability in aqueous was discussed, taking both kinetic and structural studies into consideration; and finally, study regarding mushroom tyrosinase in the presence of ILs and their associated anions was to illustrate the cooperative functioning of IL cations and anions in affecting enzyme performance, the Hofmeister series. Design and use of water-mimicking ILs composed of chaotropic cations anions may facilitate the applications of ILs in biotransformations. (C) 2009 Elsevier B.V. All rights reserved.