If it is accepted that the information for how a protein is intended to fold lies within its primary sequence, explain why a purified protein denatured in vitro might not be able to renature accurately.

Denaturation and renaturation are properties of protein but in some cases denaturation is irreversible and protein is unable to renature.

The primary sequence of a protein determines which portion of protein fold closely together in order to form three-dimensional conformation and the conformations are held by hydrogen bonds.

Denaturation of protein in-vitro is generally obtained by increasing temperature. Heat or high temperature disrupts hydrogen bonds that held between protein folds because high temperature increases the kinetic energy and the bonds are disrupted due to rapid heating. Disruption of hydrogen bonds will change the 3D structure of the protein and denatured proteins lose its function.

Chemicals are also used to disrupt hydrogen bonds such as alcohol.

So, high temperature and chemicals denature protein by affecting the hydrogen bonds holding 3D shape of primary sequence in protein and the change in protein becomes irreversible.