denaturing

Denaturing refers to processes that disrupt the native structure of macromolecules, most commonly proteins and nucleic acids, without necessarily breaking their covalent backbone. Denaturation alters the three-dimensional conformation and functional properties of a molecule, often rendering it inactive or changing its interactions with other molecules. The effects depend on the molecule, conditions, and duration of exposure.

Protein denaturation involves the unfolding of secondary, tertiary, or quaternary structure caused by disruption of non-covalent interactions and disulfide bonds. Common triggers include heat, extreme pH, organic solvents, salts, and detergents. Denatured proteins may lose catalytic activity or binding specificity, and can aggregate. In some cases, renaturation is possible if the denaturing conditions are removed and the protein can refold; in others, misfolding prevents recovery.

DNA denaturation, or strand separation, occurs when the double helix diverges into single strands. This can be achieved by heating beyond the melting temperature, exposure to high or low pH, or chemical denaturants such as formamide. Denatured DNA can re-hybridize when conditions return to non-denaturing. Denaturation is exploited in techniques such as PCR, Southern and northern blotting, and DNA sequencing preparations.

In food science, heating of proteins during cooking denatures them, contributing to texture changes and digestibility. In industry, the term denatured is also used for ethanol that has been chemically modified with additives to render it unsuitable for drinking, known as denatured alcohol. Denaturation is a general concept used across biology, chemistry, and materials science to describe loss of native structure due to external stress.