Denaturation causes a protein to lose its biological function. For example, a denatured enzyme would no longer be able to catalyze a reaction.
Denaturation does not alter the protein's structure, nor does it hydrolyze the peptide bonds. While it causes the protein's structure to unfold, the amino acids forming it remain. Following denaturation, a protein cannot fulfill its biological role. This means an enzyme can no longer catalyze its target reaction, and insulin cannot target molecules to aid the movement of glucose into cells. When using heat to denature a protein, there are some instances where cooling it down can restore its function. However, in most cases the alteration is permanent.
There are several ways to denature a protein. Using salt, urea, acids and bases and heat interrupts the bonds between hydrogen and amides, which in turn causes it to lose its structure. When it comes to tertiary proteins, this may mean losing a hydrogen bond, disulfide bond, salt bridge and non-polar covalent bonds. Because of this, there is a broad number of substances that lead to denaturation. Heat can be used to break non-polar covalent bonds and hydrogen bonds. It is because of this that heat is a useful tool for sterilizing medical supplies and food preparation areas.