Hofmeister series and individual ion contribution of ionic liquids to the enzyme activity and enantioselectivity

I&EC 136

Hua Zhao, Sophia Campbell, Lee Jackson, Olarongbe Olubajo, and Zhiyan Song. Chemistry Program, Savannah State University, Savannah, GA 31404
Hofmeister series is a list of ions in an order of their abilities in stabilizing proteins based on their kosmotropicity. It has been well established that kosmotropic anions and chaotropic cations stabilize proteins, while chaotropic anions and kosmotropic cations destabilize them. Many studies also concluded that the same principle is applicable to the enzyme stabilization in aqueous solutions.

Hydrophilic ionic liquids dissociate into individual ions in aqueous environment. Therefore, the effect of ionic liquids on the enzyme activity and stability can be correlated to the individual contributions from cations and anions. This hypothesis was examined and supported by our data on the protease activity, stability and enantioselectivity in aqueous solutions of ionic liquids with varying degrees of kosmotropicity of cations and anions. Our preliminary finding indicated that Hofmeister series could be an empirical guideline for choosing ionic liquids for enzymatic reactions in aqueous solutions.