The possible application of enzymatic transformations and clean biotechnological process by means of ionic liquid (IL) based media has continued to drive research in this are. Relatively few biochemical characterizations of protein molecules in systems containing ionic liquids (ILs) exist in literature and therefore the effects of various ILs on enzymatic reactions are not known. It is therefore important to establish a general understanding of structure-function relationships for enzymes in IL media. This calls for systematic studies in this field.
This work presents the details of the researchers’ investigation into the behaviors of two proteins within the aqueous mixtures of the entirely water miscible IL, 1-butyl-3-methylimidazolium chloride, [bmim]Cl. The measurements were done using the small- angle scattering technique, using neutrons and X-rays (SANS and SAXS, respectively) and circular dichroism spectroscopy (CD). The two model proteins used were equine heart cytochrome c and human serum albumin, HSA which are of two of the most thoroughly characterized proteins. Both equine heart cytochrome c and HSA were found to be denatured by high concentrations of [bmim]Cl. The effect of [bmim]Cl on the proteins was not particularly pronounced until the aqueous solution reached 50% [bmim]Cl
