Which condition can lead to protein denaturation?

High temperatures can lead to protein denaturation because they disrupt the weak interactions, such as hydrogen bonds and van der Waals forces, that maintain the protein's three-dimensional structure. When a protein is subjected to elevated temperatures, the increased kinetic energy causes these bonds to break, leading to a loss of the protein's functional conformation. This alteration in structure can impair the protein's biological activity, as the specific shape of a protein is essential for its function.

In contrast, reactions with sugars, combining with nucleic acids, and maintaining a stable pH do not typically result in the same level of structural disruption. While certain reactions or environmental conditions can affect protein stability, they do not generally lead to the dramatic unfolding and loss of function caused by high temperatures.