Answer to Question #207444 in Physical Chemistry for Kareena Max

Question

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 temperature–composition diagram shown in Figure 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.

Answer 1

(I) For cytochrome C and some other proteins, molten globule tends to be thermodynamic state different from native and denatured state, showing existence of third equilibrium (intermediate state). Hence, it is stable.

(ii) The polymer tends to be soluble since the solubility of protein is considered to be the proportion of nitrogen in the protein product that is in a response state under certain conditions. Solubility is a measure of the protein in a sample that responds to solubilization. The protein recommended as a food pairing can partially or fully respond, or there is no remedy in the water.