denature

Denature is a verb meaning to alter or ruin the natural character or properties of something, typically in a way that makes it unusable for its original purpose. In scientific contexts, denaturation describes the loss of native structure and function in biological macromolecules, or the chemical modification of a substance to remove its typical properties.

Protein denaturation involves disruption of noncovalent interactions that maintain secondary and tertiary structure, and may involve breaking disulfide bonds through reducing agents. It does not typically break peptide bonds, so the primary sequence remains intact in many cases. Causes include heat, extreme pH, organic solvents, detergents, and high salt.

Denatured alcohol refers to ethanol mixed with additives such as methanol, isopropanol, acetone, or bitterants to deter drinking. The resulting mixture is intended for industrial use—solvents, fuels, or cleaning products—and is not subject to beverage taxes. Denaturants are selected to render the product undrinkable while maintaining its usefulness for other applications; regulations vary by country.

Etymology: from Latin de- “removal” + natura “nature.” See also renaturation.