Disulfide bonds determine the properties of many proteins. A number of natural proteins are very rich in disulfide bonds and their mechanical properties (tensile strength, viscosity, hardness, etc.) are correlated with the degree of disulfide bonding. For example, glutenin, a wheat protein rich in disulfide bonds, is responsible for the cohesive and elastic character of dough made from wheat flour. The hard, tough nature of tortoise shell is due to the extensive disulfide bonding in its α-keratin.
What is the molecular basis for the correlation between disulfide bond content and mechanical properties of the protein? Then compare disulfide bonds with the other class of bonds discussed in class (and in the book) and how these other bonds influence protein folding. Two examples of other bond types are sufficient.