The room-temperature liquid salt, ethylammonium nitrate (EAN), has been use
d to enhance the recovery of denatured-reduced hen egg white lysozyme (HEWL
). Our results show that EAN has the ability to prevent aggregation of the
denatured protein. The use of EAN as a refolding additive is advantageous b
ecause the renaturation is a one-step process. When HEWL was denatured redu
ced using routine procedures and renatured using EAN as an additive, HEWL w
as found to regain 75% of its activity. When HEWL was denatured and reduced
in near EAN, dilution resulted in over 90% recovery of active protein. An
important aspect of this: process is that renaturation of HEWL occurs at co
ncentrations of 1.6 mg/mL, whereas other renaturation processes occur at si
gnificantly lower protein concentrations. Additionally, the refolded-active
protein can be separated from the molten salt by simple desalting methods.
Although the use of a low-temperature molten salt in protein renaturation
is unconventional, the power of this approach lies in its simplicity and ut
ility.