denatured

Denatured is a term used to describe a substance whose native structure or quality has been altered by a physical, chemical, or biological process, without changing its basic chemical identity. In biology and chemistry, denaturation typically refers to proteins or nucleic acids losing their functional conformation while remaining chemically intact in composition.

Protein denaturation refers to the unfolding of a protein's three-dimensional structure, disrupting secondary, tertiary, and sometimes quaternary structure. Causes include heat, changes in pH, detergents, organic solvents, or salts. Denaturation can be reversible if the original structure is restored, but it is often irreversible and may lead to aggregation and loss of activity.

DNA denaturation describes the separation of double strands into single strands, usually by heat or chemical agents that disrupt hydrogen bonding. This process is exploited in laboratory techniques such as polymerase chain reaction and sequencing, where access to single-stranded DNA is required.

Denatured alcohol is ethanol rendered unsuitable for drinking by adding denaturants such as methanol, isopropanol, or bittering agents. The aim is to deter consumption and avoid beverage taxes and regulations. Denatured products are used as solvents, fuels, and cleaning agents, and are regulated to prevent harmful use; they can pose toxic risks if ingested.

For both biological macromolecules and consumer products, denaturation indicates a functional or perceptual change rather than a change in chemical composition, and the reversibility and consequences of denaturation depend on the system and conditions.