Kinetic determinism of lysozyme folding at high temperatures

Reduced, disordered hen egg lysozyme rapidly regains enzymic activity in a nonenzymic system previously reported from this laboratory. When such regenerations are carried out at high temperatures (where the native enzyme is unstable), native enzyme is formed as a transient intermediate. Thermal inactivation does not depend on irreversible changes in the protein, as shown by experiments wherein thermally inactivated regenerated lysozyme spontaneously reactivates at 37°. These findings are inconsistent with thermodynamic determinism of protein structure.