| buffer | <biochemistry, chemistry> A system that acts to minimise the change in concentration of a specific chemical species in solution against addition or depletion of this species. PH buffers: weak acids or weak bases in aqueous solution. The working range is given by pKa +/ 1. Metal ion buffers: a metal ion chelator for example EDTA, partially saturated by the metal ion acts, as a buffer for the metal ion. (18 Nov 1997) |
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| buffer capacity | <chemistry> The ability of a buffer solution to absorb added alkali or acid while maintaining the solution's pH. (09 Oct 1997) |
| buffer index | The power of a substance in solution to absorb acid or alkali without change in pH; this is highest at a pH value equal to the pKa value of the acid of the buffer pair. See: buffer capacity. Synonym: buffer index. (05 Mar 2000) |
| buffer pair | An acid and its conjugate base (anion). (05 Mar 2000) |
| buffer value | The power of a substance in solution to absorb acid or alkali without change in pH; this is highest at a pH value equal to the pKa value of the acid of the buffer pair. See: buffer capacity. Synonym: buffer index. (05 Mar 2000) |
| buffer value of the blood | The ability of the blood to compensate for additions of acid or alkali without disturbance of the pH. (05 Mar 2000) |
| buffer zone | <ecology> An area of land separating two distinct land uses that acts to soften or mitigate the effects of one land use on the other. (09 Oct 1997) |
| riparian buffer | Riparian areas that are managed to protect the aquatic and riparian ecosystem. A riparian buffer protects water quality and temperature, habitat along the banks, upland habitat for aquatic and riparian species, and some or all of the floodplain. (05 Dec 1998) |
| secondary buffer | See: Hamburger's law. (05 Mar 2000) |
| dipolar buffer | Buffer whose structure can include opposite charges. Synonym: dipolar buffer. (05 Mar 2000) |
| zwitterionic buffer | Buffer whose structure can include opposite charges. Synonym: dipolar buffer. (05 Mar 2000) |
| acetoacetyl-acyl carrier protein synthase | <enzyme> E coli enzyme, that catalyses condensation of malonyl-acyl carrier protein plus acetyl-acyl carrier protein; not inhibited by cerulenin Registry number: EC 2.3.1.- Synonym: acetoacetyl-acp synthase (26 Jun 1999) |
| acid soluble spore protein | <molecular biology> A DNA binding protein in the spores of some bacteria, thought to stabilise the DNA in an A configuration, so protecting it from cleavage by enzymes or UV light. (18 Nov 1997) |
| acute-phase protein | <haematology> These plasma proteins (in addition to fibrinogen) increase 25% or more in response to inflammation and injury are under direct control of interleukin-6 (IL-6) (hepatocyte-stimulating factor). Other proteins which increase are ceruloplasmin, C3 and C4 which increase 50% or more; alpha-1 acid glycoprotein, alpha-1 antitrypsin, haptoglobin and fibrinogen (the major determinant of viscosity 1 ) which increase two- to fourfold; C-reactive protein (CRP) and serum amyloid A which increase several hundred-fold. Despite long-held clinical opinion to the contrary, available data indicate that neither ESR nor measurement of specific acute-phase reactants are useful in excluding underlying infection or inflammation regardless of the pretest probability. These proteins are secreted into the blood in increased or decreased quantities by hepatocytes in response to trauma, inflammation, or disease. They can serve as inhibitors or mediators of the inflammatory processes. Certain acute-phase proteins have been used to diagnose and follow the course of diseases or as tumour markers. See also: amyloid, c-reactive protein, erythrocyte sedimentation rate, viscosity. (25 Jun 1999) |
| acyl-(acyl-carrier-protein)-phospholipid acyltransferase | <enzyme> Catalyses the formation of phosphatidylethanolamine from acyl-acyl carrier protein and 2-acyl-sn-glycero-3-phosphoethanolamine Registry number: EC 2.3.1.40 Synonym: 2-acyl-gpe acyltransferase, 2-acylglycerophosphoethanolamine acyltransferase (26 Jun 1999) |