denaturation

See denaturant.

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Biochemical process modifying a protein's natural configuration.

It involves breaking many weak (hydrogen and hydrophobic) bonds (see bonding) that maintain the protein's highly ordered structure. This usually results in loss of biological activity (e.g., loss of an enzyme's ability to catalyze reactions). Denaturation can be brought about by heating; treatment with alkalis, acids, urea, or detergents; or even vigorous shaking of the protein solution. It can be reversed in some cases (e.g., serum albumin, hemoglobin), if conditions favourable to the protein are restored, but not in others. The term is also used to describe the process of rendering ethanol unfit to drink.

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▪ biology

      in biology, process modifying the molecular structure of a protein. Denaturation involves the breaking of many of the weak linkages, or bonds (e.g., hydrogen bonds), within a protein molecule that are responsible for the highly ordered structure of the protein in its natural (native) state. Denatured proteins have a looser, more random structure; most are insoluble. Denaturation can be brought about in various ways—e.g., by heating, by treatment with alkali, acid, urea, or detergents, and by vigorous shaking.

      The original structure of some proteins can be regenerated upon removal of the denaturing agent and restoration of conditions favouring the native state. Proteins subject to this process, called renaturation, include serum albumin from blood, hemoglobin (the oxygen-carrying pigment of red blood cells), and the enzyme ribonuclease. The denaturation of many proteins, such as egg white, is irreversible. A common consequence of denaturation is loss of biological activity (e.g., loss of the catalytic ability of an enzyme).

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