Chaotropic agent

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A chaotropic agent', also known as chaotropic reagent and chaotrope, is a substance which disrupts the three dimensional structure in macromolecules such as proteins, DNA, or RNA and denatures them. Chaotropic agents interfere with stabilizing intra-molecular interactions mediated by non-covalent forces such as hydrogen bonds, Van der Waals forces, and hydrophobic effects.

Often structural features, as detected by means such as circular dichroism can be titrated in a chaotrope concentration-dependent fashion.

Chaotropic reagents include:

• Urea 6 - 8 mol/l
• Guanidinium chloride 6 mol/l
• Lithium perchlorate 4.5 mol/l

High generic salts can have chaotropic properties, by shielding charges and preventing the stabilization of salt bridges. Hydrogen bonding is stronger in nonpolar media, so salts, which increase the dipole moment of the solvent, can also destabilize hydrogen bonding.

[edit] See also

• Kosmotropic
• Hofmeister series
• Denaturation (biochemistry)