* In quaternary structure denaturation, protein sub-units are dissociated and/or the spatial arrangement of protein subunits is disrupted.
* Tertiary structure denaturation involves the disruption of:
** Covalent interactions between amino acid side-chains (such as disulfide bridges between cysteine groups)
** Non-covalent dipole-dipole interactions between polar amino acid side-chains (and the surrounding solvent)
** Van der Waals (induced dipole) interactions between nonpolar amino acid side-chains.
* In secondary structure denaturation, proteins lose all regular repeating patterns such as alpha-helices and beta-pleated sheets, and adopt a random coil configuration.
* Primary structure, such as the sequence of amino acids held together by covalent peptide bonds, is not disrupted by denaturation.