chaotropic: what's it mean?

[Vladimir Svetlov]

In article <mwcrepeau-2808981757410001 at curt.ucdavis.edu>,
mwcrepeau at ucdavis.edu (Marc Crepeau) wrote:

> What does this word mean?  Nobody I've asked seems to know.  I am
> referring to chaotropic as in the "chaotropic salts" which are used in
> Qiagen DNA purification kits.

Chaotropic is a term in protein chemistry referring to a solvent or solute
that has propensity (tropos) to induce disordered state (unfolded/thus
chaos) in proteins. Examples of such solutes are guanidinium chloride and
urea. A related term is cosmotropic - something with propensity to
induce/maintain ordered (folded/thus cosmos) state, examples or cosmotropic
solutes are ammonium sulfate and arginine.

Regards,
V.