Reversed micelles as novel protein refolding media

Refolding of denatured RNase A was conducted by a nanostructural surfactant-based molecular assembly formulated with sodium di-2-ethylhexyl sulfosuccinate (AOT) in isooctane. In the novel refolding technique, a solid-liquid extraction was utilized as an alternative to the ordinary protein extraction by reversed micelles based on a liquid-liquid extraction. The effects of operational parameters such as concentration of AOT, Wo (=[H₂O]/[AOT]), and pH were examined on the solubilization of denatured proteins into a reversed micellar solution. The typically denatured form of the protein being isolated is reactivated due to its refolding ability within the confines of the reversed micelle medium. A complete renaturation of RNase A was accomplished by adjusting the composition of the redox reagent even at a high protein concentration in which protein aggregation would usually occur in aqueous media. In the final step, the renatured RNase A was effectively recovered from the reversed micellar solution without the loss of the enzymatic activity.