Egg white ovalbumin: The unfolding of ovalbumin, a 45 kDa protein, as a function of guanidine hydrochloride (0-6M) occurred reversibly in one step.  The protein fractions in native (N) and the denatured states (D) were characterized by UV spectrometry and viscosity measurements at defined temperatures in buffer pH 7.0. The thermodynamics of folding and possibly kinetics followed a two state transition (N->D). The data were consistent with the fact that the native state was stabilized by hydrophobic effect in aqueous solution; this effect was diminished by introducing Guanidine hydrochloride to protein solution with concomitant transition to denatured state, random coil conformation similar to a nascent polypeptide chain.  
Egg white Ovomucoid: The unfolding of ovomucoid (N), a domain containing 28 kDa protein, by guanidine hydrochloride did not proceed in a single step but occurred in two steps; the transition at low denaturant was associated with an intermediate, native-like, structure (X), and at high denaturant, protein existed in random coil structure (D). The reversible unfolding at each step (N->X->D) followed a two state transition pattern, albeit with somewhat different folding rates for the intermediate and native structures (1978). The studies in his lab indicated that in vivo protein folding may not be explained by the amino acid sequence alone. Independently, the molecular biology of chaperones succeeded in the identification of additional folding factors in 1989. The latter studies marked the beginning of modern protein folding with manipulation in human health.