Chaotropic activity

Chaotropicity describes the entropic disordering of lipid bilayers and other biomacromolecules which is caused by substances dissolved in water. According to the original usage^[1] and work carried out on cellular stress mechanisms and responses,^[2][3][4] chaotropic substances do not necessarily disorder the structure of water.^[5]

The chaotropic activities of solutes in the aqueous phase (e.g. ethanol, butanol, urea, MgCl₂ and phenol) have been quantified using an agar-gelation assay.^[6] Whereas chaotropicity was first applied to studies of ions,^[1] it is equally applicable to alcohols, aromatics, ion mixtures and other solutes.^[2][3][7][8] Furthermore, hydrophobic substances known to stress cellular systems (including benzene and toluene) can chaotropically disorder macromolecules, and induce a chaotrope-stress response in microbial cells, even though they partition into the hydrophobic domains of macromolecular systems.^[4][9]

References

1. Hamaguchi & Geiduschek (1962). "The Effect of Electrolytes on the Stability of the Deoxyribonucleate Helix". J. Am. Chem. Soc. 84 (8): 1329–1338. doi:10.1021/ja00867a001.
2. Hallsworth, J.E. (1998). "Ethanol-induced water stress in yeast". Journal of Fermentation and Bioengineering. 85 (2): 125–137. doi:10.1016/S0922-338X(97)86756-6.
3. Hallsworth, J.E., Heim, S. and Timmis, K. (2003). "Chaotropic solutes cause water stress in Pseudomonas putida". Environmental Microbiology. 5 (12): 1270–1280. doi:10.1111/j.1462-2920.2003.00478.x. PMID 14641573.{{cite journal}}: CS1 maint: multiple names: authors list (link)
4. Bhaganna, P.; et al. (2010). "Hydrophobic substances induce water stress in microbial cells". Microbial Biotechnology. 3 (6): 701–716. doi:10.1111/j.1751-7915.2010.00203.x. PMC 3815343. PMID 21255365.
5. Ball, P.; Hallsworth, J.E. (2015). "Water structure and chaotropicity: their uses, abuses and biological implications". Physical Chemistry Chemical Physics. 17 (13): 8297–8305. Bibcode:2015PCCP...17.8297B. doi:10.1039/C4CP04564E. PMID 25628033.
6. Cray, J.A.; et al. (2013). "A universal measure of chaotropicity and kosmotropicity". Environmental Microbiology. 15 (1): 287–296. doi:10.1111/1462-2920.12018. PMID 23145833.
7. Hallsworth, J.E.; et al. (2007). "Limits of life in MgCl₂-containing environments: chaotropicity defines the window". Environmental Microbiology. 9 (3): 801–813. doi:10.1111/j.1462-2920.2006.01212.x. PMID 17298378.
8. Alves, F.L.; et al. (2015). "Concomitant osmotic and chaotropicity-induced stresses in Aspergillus wentii: compatible solutes determine the biotic window". Current Genetics. 61 (3): 457–477. doi:10.1007/s00294-015-0496-8. PMID 26055444. S2CID 14826577.
9. Cray, J.A.; et al. (2015). "Chaotropicity: a key factor in product tolerance of biofuel-producing microorganisms". Current Opinion in Biotechnology. 33: 228–259. doi:10.1016/j.copbio.2015.02.010. PMID 25841213.