| heat-shock protein | <cell biology, molecular biology, protein> Families of proteins conserved through prokaryotic and eukaryotic cells and bacteria in response to hyperthermia and other environmental stresses, although some are constitutively expressed. They increase thermal tolerance and perform functions essential to cell survival under these conditions. Some serve to stabilise proteins in abnormal configurations, play a role in folding and unfolding of proteins and the assembly of oligomeric complexes and may act as chaperonins. Hsp90 complexes with inactive steroid hormone receptor and is displaced upon ligand binding. Four major sub classes are recognised: hsp90, hsp70, hsp60 and small hsps. Hsps have been suggested to act as major immunogens in many infections. Acronym: HSP (12 Dec 1998) |
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| heat-shock protein 27 kinase | <enzyme> Phosphorylates hsp 26 on serine residues when stimulated by tumour necrosis factor or interleukin 1 Registry number: EC 2.7.1.- Synonym: hsp 27 kinase, heat-shock protein 27 kinase, hsp27 kinase (26 Jun 1999) |
| heat-shock proteins 70 | <cell biology, protein> A class of molecular chaperones found in both prokaryotes and in several compartments of eukaryotic cells. There is evidence that these proteins can interact with polypeptides during a variety of assembly processes in such a way as to prevent the formation of nonfunctional structures. (12 Dec 1998) |
| heat-shock proteins 90 | <cell biology, protein> A class of molecular chaperones whose members act in the mechanism of signal transduction by steroid receptors. (12 Dec 1998) |
| heat-shock response | <cell biology> A constellation of responses that occur when an organism is exposed to excessive heat and other environmental stresses. Responses include synthesis of some proteins, repression of other proteins, and expression of new proteins. (12 Dec 1998) |
| heat-shock response element | <cell biology, protein> The nucleotide sequence, CNNGAANNTCCNG, which is in the promoter region of the heat-shock genes. When the animal is exposed to certain types of stress such as a sudden rise in temperature, the first thing that happens to activate these genes is the binding of the HSE by a transcriptional enhancer protein. (09 Oct 1997) |
| heat-stable | Thermostable Not readily subject to alteration or destruction by heat. Synonym: heat-stable. Origin: thermo-+ L. Stabilis, stable (05 Mar 2000) |
| heat-stable enzyme | <enzyme> An enzyme that is not readily subject to destruction or alteration by heat. Synonym: heat-stable enzyme. (05 Mar 2000) |
| heat stress disorder | A group of conditions due to overexposure to or overexertion in excess environmental temperature. It includes heat cramps, which are non-emergent and treated by salt replacement; heat exhaustion, which is more serious, treated with fluid and salt replacement; and heatstroke, a condition most commonly affecting extremes of age, especially the elderly, accompanied by convulsions, delusions, or coma and treated with cooling the body and replacement of fluids and salts. (12 Dec 1998) |
| heat transfer efficiency | Useful heat output released to the room divided by the actual heat produced in the firebox (17 Dec 1998) |
| heat treatment | In dentistry, a method of controlled temperature handling of metals so as to change the microscopic structure and thus the physical properties. See: temper, anneal. (05 Mar 2000) |
| heat urticaria | A form of physical or non-allergic urticaria initiated by heat (e.g., hot baths, physical exercise, pyrexia, exposure to sun or to a warm room) or by excitement; the rather distinctive lesions consist of pruritic areas 1 to 2 mm in diameter surrounded by bright red macules. Synonym: heat urticaria. (05 Mar 2000) |
| process heat | Heat used in an industrial process rather than for space heating or other housekeeping purposes. (05 Dec 1998) |
| sensible heat | The amount of heat that, when absorbed by a substance, causes a rise in temperature. Compare: latent heat. (05 Mar 2000) |
| specific heat | The amount of energy (measured in calories or joules) needed to raise thetemperature of one gram of a pure substance by one degree C. (09 Oct 1997) |