Studies on the Refolding of Egg White Lysozyme Denatured by Urea Using "Phase Diagram" Method of Fluorescence

Abstract

The refolding of reduced and non-reducing egg white lysozymes in a urea solution was studied by a "phase diagram" method of fluorescence. The result showed that in the refolding of the reduced egg white lysozyme, an intermediate state of an egg white lysozyme exists at the urea concentrations in a final renaturation solution being about 4.5 mol/L, their refolding follows a three-state model; while in the refolding of the non-reducing egg white lysozyme, two intermediate states exist at the urea concentrations being separately 4.0 and 2.5 mol/L, and their refolding follows a four-state model. Through the comparison between the unfolding and refolding of an egg white lysozyme in the urea solution, it was found that both of the refolding of reduced and non-reducing egg white lysozyme molecules was irreversible to their unfolding in the urea solution. Finally, a suggested refolding was separately presented for the reduced and non-reducing egg white lysozymes in the urea solution.

Stability and enzyme activity of lysozyme in the presence of Fe3O4 nanoparticles

“…Hen egg white lysozyme (HEWL) is a similar lysozyme and the most widely used protein for model system study. Hen egg white lysozyme (Lyz) is a small monomeric globular protein that includes structure elements usually found in proteins, containing a-helix, b-sheet, turns and disorder, and formed by 129 amino residues including six tryptophans, three tyrosines, and four disulfide bonds [36][37][38]. Four disulfide bonds connecting eight cysteines are very strong and protect HEWL from completely unfolding [39].…”