Protein denaturation by interaction with metals

Heavy metals that interact with proteins are usually found in the form of salts. Therefore, they can interact with the salt bridges between amino acids. However, heavy metals may also disrupt disulfide bonds because of their high affinity and attraction for sulfur. The final result of this interaction is an insoluble metal-protein salt.

Since most heavy metal salts are toxic for humans, they are used selectively, for instance, as tools for cooking. Copper bowls are preferred by chefs when they need to prepare an egg white foam because copper ions stabilize the denatured egg whites.

On the other hand, proteins are also used in the case of heavy metal poisoning. Milk or egg whites consumption is recommended as an antidote because an insoluble solid is formed (a protein-heavy metal precipitate) that needs to be removed immediately from the stomach before the gastric acid denatures the proteins and sets the heavy metal free again.