Heat denaturation of ribonuclease.

One of the main and, chronologically, perhaps one of the first questions in the study of globular protein heat denaturation is that of the applicability of the "all or none" principle to this process, i.e., whether the transition of globular protein from the native into the denaturated state occurs abruptly, without intermediate, thermodynamically stable forms or there are several successive transitions. Despite an intensive study of the process of denaturation this question still remains unsettled. Moreover, its actuality has greatly increased lately with the accumulation of contradictory data.