Osmolyte

Osmolytes are compounds affecting osmosis^[1]. They are soluble in the solution within a cell, or in the surrounding fluid, e.g. as plasma osmolytes. They play a role in maintaining cell volume and fluid balance. For example, when a cell swells due to external osmotic pressure, membrane channels open and allow efflux of osmolytes which carry water with them, restoring normal cell volume.^[2]

Natural osmolytes that can act as osmoprotectants include trimethylamine N-oxide (TMAO), dimethylsulfoniopropionate, trimethylglycine, sarcosine, betaine, glycerophosphorylcholine, myo-inositol, taurine and others.^[3] In humans, osmolytes are of particular importance in the renal medulla.^[4]

References

1. ^ everythingbio.com
2. ^ Review of Medical Physiology, William F. Ganong, McGraw-Hill Medical, ISBN 978-0071440400.
3. ^ Neuhofer, W.; Beck, F. X. (2006). "Survival in Hostile Environments: Strategies of Renal Medullary Cells". Physiology 21 (3): 171–180. doi:10.1152/physiol.00003.2006. PMID 16714475.  edit
4. ^ Gallazzini, M.; Burg, M. B. (2009). "What's New About Osmotic Regulation of Glycerophosphocholine". Physiology 24 (4): 245–249. doi:10.1152/physiol.00009.2009. PMC 2943332. PMID 19675355. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2943332.  edit

Further reading

• Rose GD, Fleming PJ, Banavar JR, Maritan A (November 2006). "A backbone-based theory of protein folding". Proc. Natl. Acad. Sci. U.S.A. 103 (45): 16623–33. doi:10.1073/pnas.0606843103. PMC 1636505. PMID 17075053. http://www.pnas.org/cgi/pmidlookup?view=long&pmid=17075053. 
• Yancey PH (August 2005). "Organic osmolytes as compatible, metabolic and counteracting cytoprotectants in high osmolarity and other stresses". J. Exp. Biol. 208 (Pt 15): 2819–30. doi:10.1242/jeb.01730. PMID 16043587. http://jeb.biologists.org/cgi/pmidlookup?view=long&pmid=16043587. 
• Holthauzen LM, Bolen DW (February 2007). "Mixed osmolytes: the degree to which one osmolyte affects the protein stabilizing ability of another". Protein Sci. 16 (2): 293–8. doi:10.1110/ps.062610407. PMC 2203298. PMID 17189473. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2203298.