- Thermostability
Thermostability is the quality of a substance to resist irreversible change in its chemical or physical structure at a high relative temperature.
Thermostable materials may be used industrially as
fire retardant s. A "thermostableplastic ", an uncommon and unconventional term, is likely to refer to athermosetting plastic that cannot be reshaped when heated, than to athermoplastic that can be remelted and recast. Thermostability also commonly refers to aprotein resistant to irreversible change in itsprotein structure due to applied heat.Thermostable proteins
Most life-forms on Earth live at temperatures of less than 50 °C, commonly from 15 °C to 50 °C. Above this, thermal energy may cause the unfolding of the protein structure to be irreversible, a condition understandably deleterious to continuing life-functions. The denaturing of proteins in albumen from a clear, nearly colourless liquid to an opaque white, insoluble gel is a common example of this.
Certain thermophilic life-forms exist which can withstand temperatures above this. Examining homologous proteins present in these thermophiles and other organisms reveal only slight differences in the protein structure. One notable difference is the presence of extra
hydrogen bond s in the thermophile's proteins—meaning that the protein structure is more resistant to unfolding. The presence of certain types ofsalt has been observed to decrease thermostability in the proteins ofmesophile s but not ofhyperthermophile s which may indicate that salt bridges have more impact on thermostability at high temperature than is currently widely acknowledged.Thermostable
enzyme s such asTaq polymerase andPfu DNA polymerase are used inpolymerase chain reaction s where temperatures of 94 °C or over are used to melt apartDNA strands.Thermostable toxins
Certain
poison ousfungi contain thermostabletoxin s, such asamatoxin found in thedeath cap and autumn skullcapmushroom s.ee also
Thermophiles
*Thermus thermophilus
*Thermus aquaticus
*Pyrococcus furiosus External links
* [http://www.jyi.org/volumes/volume6/issue1/articles/kaeberlein.html A Comparison of the Thermostability of Glyceraldehyde 3-phosphate Dehydrogenase From Thermophiles and Mesophiles in Different Ionic Salt Solutions]
* [http://www.funpecrp.com.br/GMR/year2003/vol4-2/gmr0079_full_text.htm Preferred amino acids and thermostability]
* [http://homepages.uel.ac.uk/S.Doonan/thermo.html Thermostability of Proteins]
* [http://www.cryst.bbk.ac.uk/PPS2/projects/day/TDayDiss/SaltBridges.html Salt Bridges]
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