The unfolding, or denaturation, of a biological macromolecule may be brought about by

Chapter 6, Problem 6.13

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The unfolding, or denaturation, of a biological macromolecule may be brought about by treatment with substances, called denaturants, that disrupt the intermolecular interactions responsible for the native three-dimensional conformation of the polymer. For example, urea, CO(NH2)2, competes for NH and CO groups and interferes with hydrogen bonding in a polypeptide. In a theoretical study of a protein, the temperaturecomposition diagram shown in Fig. 6.47 was obtained. It shows three structural regions: the native form, the unfolded form, and a molten globule form, a partially unfolded but still compact form of the protein. (i) Is the molten globule form ever stable when the denaturant concentration is below 0.1? (ii) Describe what happens to the polymer as the native form is heated in the presence of denaturant at concentration 0.15.