[Protein stability to the effect of denaturing agents and elevated temperature is directly proportional to the fraction of hydrophobic residues in its molecule].

The dependence of protein stability against the action of urea, guanidine hydrochloride and elevated temperature on the fraction of hydrophobic residues in their molecules was studied. It was shown that proteins can be divided into several stability classes. The stability of proteins within each class is directly proportional to the fraction of hydrophobic residues in their molecules and this dependence is a linear one. As shown on several examples proteins can pass from one class to another and such discrete transitions are determined by the formation or disruption of bonds with cofactors. The effect of point mutations on the stability of proteins is discussed from the viewpoint of polar group dehydration.