Determination of Myoglobin Stability by Visible Spectroscopy

A simple system for the determination of protein stability by denaturation is described. The denaturation of myoglobin by the chaotropic salt guanidium hydrochloride is readily and reproducibly followed at 409 nm, and the free energy of stabilization of the native protein is derived from a straightforward mathematical analysis of the denaturation profile. The use of a well-characterized protein and an inexpensive procedure make this an attractive experiment for general use. Several complementary biophysical experiments are also possible, including the varying of denaturants, temperature, or myoglobin source.