(1) A process in which the folding structure of a protein is altered due to exposure to certain chemical or physical factors (e.g. heat, acid, solvents, etc.), causing the protein to become biologically inactive.
(3) The process of making food or drink (e.g. alcohol) unfit for human consumption by the deliberate addition of a noxious substance.
Biological proteins (such as enzymes) unfold and lose their active state when exposed to denaturing agents (e.g. strong acids or bases, heat, solvents, and salts). This is crucial especially when enzymes lose their structure and function as catalysts. The substrates can no longer bind to the active site, and biochemical process is therefore disrupted. The proteins can regain their natural active state if the denaturing agent is removed. However, there are instances in which the process is irreversible.
Related term: alkali denaturation test