To determine a protein’s thermodynamic stability, chemical denaturation studies can be performed. assuming that only the native and unfolded states can be observed under experimentally available conditions, what is the most likely shape of the curve for the dependence of the fraction of folded protein upon denaturant concentration?

The curve obtained is hyperbolic.

Step-by-step explanation:

When talking about fractions we get a total sum of 1, so: unfolded-protein fraction + folded-protein fraction = 1.

We start only with folded protein so its fraction it's 1. As we add denaturant, the amount of folded protein will start decreasing and we will just have unfolded protein.

There's a point in which we get 0.5 of unfolded protein and 0.5 of folded protein and that's called denaturant concentration 50. It represents the denaturant concentration at which 50% of the molecules are folded.