| 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) |
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| 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) |
| acyl-(acyl-carrier-protein)-UDP-N-acetylglucosamine acyltransferase | <enzyme> E coli enzyme involved in lipid a biosynthesis; uses beta-hydroxymyristoyl-acyl carrier protein to form udp-3-monoacyl-n-acetylglucosamine; amino acid sequence given in second source Registry number: EC 2.3.1.129 Synonym: udp-aguatransferase, lpxa protein, udp-n-acetylglucosamine-3-acyltransferase, udp-n-acetylglucosamine 3-o-acyltransferase, udp-3-o-(r-3-hydroxymyristoyl)glucosamine-n-acyltransferase, lpxd protein, fira gene product, fira protein (26 Jun 1999) |
| acyl carrier protein | <protein> A small (77 peptides long) protein which binds six other enzymes involved in fatty acid synthesis. It was first isolated in E. Coli bacteria. (09 Oct 1997) |
| acyl carrier protein acylase | <enzyme> From E coli Registry number: EC 2.3.1.- Synonym: acp acylase (26 Jun 1999) |
| acyl protein synthetase | <enzyme> Component of the fatty acid reductase complex of luminescent bacteria Registry number: EC 2.3.1.- Synonym: luxe gene product, fatty acyl-protein synthetase (26 Jun 1999) |
| AKT1 protein kinase | <enzyme> Human homolog of v-akt oncogene product Registry number: EC 2.7.10.- Synonym: akt1 protein, human (26 Jun 1999) |
| AMP-activated protein kinase kinase | <enzyme> An endogenous kinase kinase; reactivates the inactive form of AMP-activated protein kinase (AMP-pk); phosphorylates the 63-kD subunit of AMP-pk Registry number: EC 2.7.1.- Synonym: AMP-pk reactivator, hmg CoA reductase kinase kinase (26 Jun 1999) |
| amyloid beta-protein | A 4 kD protein, 39-43 amino acids long, expressed by a gene located on chromosome 21. It is the major protein subunit of the vascular and plaque amyloid filaments in individuals with alzheimer's disease and in aged individuals with trisomy 21 (down syndrome). The protein is found predominantly in the nervous system, but there have been reports of its presence in non-neural tissue. (12 Dec 1998) |
| amyloid beta-protein precursor | A precursor to the amyloid-beta protein (beta/a4). Alterations in the expression of the amyloid beta-protein precursor (abpp) gene, located on chromosome 21, plays a role in the development of the neuropathology common to both alzheimer disease and down syndrome. Abpp is associated with the extensive extracellular matrix secreted by neuronal cells. Upon cleavage, this precursor produces three proteins of varying amino acid lengths: 695, 751, and 770. The beta/a4 (695 amino acids) or beta-amyloid protein is the principal component of the extracellular amyloid in senile plaques found in alzheimer disease, down syndrome and, to a limited extent, in normal aging. (12 Dec 1998) |
| amyloid precursor protein | <protein> Individuals with Alzheimer's disease are characterised by extensive accumulation of amyloid in the brain, referred to as senile plaques. These consist of a core of amyloid fibrils surrounded by dystrophic neurites. The principal component of the amyloid fibrils is B/A4, a peptide derived from the larger APP. The specific role of amyloid protein is unclear but it is thought that amyloid deposits may cause neurons to degenerate. Amyloid deposits also occur in brains of older Down's Syndrome patients. (04 May 1997) |
| amyloid protein | Glycoprotein deposited extracellularly in tissues in amyloidosis. The glycoprotein may either derive from light chain of immunoglobulin (AIO (amyloid of immune origin): 5-18 kD glycoprotein, product of a single clone of plasma cells, the N terminal part of lambda or kappa light chain) or, in what used to be referred to as AUO, amyloid of unknown origin, from serum amyloid A (SAA), one of the acute phase proteins that increases many fold in inflammation. The polypeptides are organised as a _ pleated sheet making the material rather inert and insoluble. Minor protein components are also found. Should be distinguished from _ amyloid deposited in the brain and that is derived from amyloid precursor protein (see amyloidogenic glycoprotein. (18 Nov 1997) |
| amyloid protein aa | A nonimmunoglobulin amyloid isolated from amyloid fibrils deposited in amyloidosis secondary to chronic inflammatory diseases such as rheumatoid arthritis. Antisera to amyloid protein aa have been used to detect a related serum protein saa. (12 Dec 1998) |
| amyloid protein saa | A serum protein believed to be a circulating precursor to amyloid protein aa. It is present in low concentrations in normal sera, but found in much higher concentrations in sera of older persons and in patients with amyloidosis or with diseases known to predispose to amyloidosis. Very high levels of this protein have been reported during acute inflammatory episodes. Antisera to amyloid protein aa cross-react with protein saa. (12 Dec 1998) |
| androgen binding protein | A protein secreted by testicular Sertoli cells along with inhibin and mullerian inhibiting substance. Androgen binding protein probably maintains a high concentration of androgen in the seminiferous tubules. (05 Mar 2000) |