What is "denaturation"

1845, earlier in French and German; see denature + -ation.

n. 1 The deliberate addition of a noxious substance to alcohol to make it unfit to drink 2 (context biochemistry English) The change of folding structure of a protein (and thus of physical properties) caused by heating, changes in pH, or exposure to certain chemicals.

Denaturation is a process in which proteins or nucleic acids lose the quaternary structure, tertiary structure and secondary structure which is present in their native state, by application of some external stress or compound such as a strong acid or base, a concentrated inorganic salt, an organic solvent (e.g., alcohol or chloroform), radiation or heat. If proteins in a living cell are denatured, this results in disruption of cell activity and possibly cell death. Denatured proteins can exhibit a wide range of characteristics, from conformational change and loss of solubility to aggregation due to the exposure of hydrophobic groups.

Protein folding is key to whether a globular protein or a membrane protein can do its job correctly. It must be folded into the right shape to function. But hydrogen bonds, which play a big part in folding, are rather weak, and it doesn't take much heat, acidity, or other stress to break some and form others, denaturing the protein. This is one reason why tight homeostasis is physiologically necessary in many life forms.

This concept is unrelated to denatured alcohol, which is alcohol that has been mixed with additives to make it unsuitable for human consumption.

'''Denaturation ''' may refer to:

• Denaturation (biochemistry), a structural change in macromolecules caused by extreme conditions
• Denaturation (fissile materials), transforming fissile materials so that they cannot be used in nuclear weapons
• Denaturation (food), intentional adulteration of food or drink rendering it unfit for consumption while remaining suitable for other uses

Denaturation of fissile materials suitable for nuclear weapons is the process of transforming them into a form that is not suitable for weapons use and can not easily be reversely transformed. For Uranium 235 this is straightforward, by mixing it with Uranium 238, but for plutonium it is more difficult and/or less effective, because other plutonium isotopes are either also suitable for weapons or not available and not practical to produce, while mixing with another element allows chemical separation.

The situation with Uranium-233 is more drastic. Decay of the attached Uranium-232 produces Thorium-228 with a radioactive half-life of 1.9 years and several short-lived daughter nuclides; these daughters include some very hard gamma-ray emitters like Thallium-208 and Lead-212. After approximately one single year the alpha activity of these decay products is several hundred curies per kilogram of U-233, and the gamma penetration radiation is a thousand times larger to some than from the plutonium. Aged U-233 is self-protected radiologically from diversion.

Category:Isotope separation

The word denature is used in two food-related contexts.