Protein breaks down into amino acids upon destruction of any structure.

Proteins have 4 levels of organization. The primary structure is formed by a sequence of amino acids, and it is this that is most important. Secondary, tertiary and quaternary (only in some proteins) structures are formed due to the adoption of a certain conformation by the amino acid chain (for example, spirals and folds are formed, the molecule folds).
Disruption of the protein structure is called denaturation. It is reversible, if the primary structure is not damaged, and then the protein can return to its shape, and irreversible, when the primary structure is broken and the polypeptide chain breaks down into separate amino acids.