| chain, orthodontic chain | <dentistry> A stretchable plastic chain used to hold archwires into brackets and to moke teeth. (08 Jan 1998) |
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| gene rearrangement, beta-chain T-cell antigen receptor | Ordered rearrangement of T-cell variable gene regions coding for the beta-chain of antigen receptors. (12 Dec 1998) |
| short-chain beta-hydroxyacyl-CoA dehydrase | <enzyme> Forms trans-2-enoyl-CoA; maximal activity with trans-2-hexenoyl-CoA, followed by crotonyl-CoA; not the same as EC 4.2.1.17 Registry number: EC 4.2.1.- Synonym: beta-hydroxybutyryl-CoA dehydrase, short-chain beta-hydroxyacyl-coenzyme a dehydrase (26 Jun 1999) |
| androst-5-ene-3 beta,17 beta-diol | <chemical> An adrenal-derived oestrogenic metabolite of dhea. Evidence exist for its use as an endocrine regulator of immune response. Pharmacological action: anabolic steroids. Chemical name: Androst-5-ene-3,17-diol, (3beta,17beta)- (12 Dec 1998) |
| beta-1,3-galactosyl-0-glycosyl-glycoprotein beta-1,3-N-acetylglucosaminyltransferase | <enzyme> Capable of adding a glcnac residue to g1cnacman(3)g1cnac; from mung bean seedlings Registry number: EC 2.4.1.146 Synonym: n-acetylglucosaminyltransferase II, gal3-(glcnac6)galnac-mucin (glcnac--gal)3-glcnactransferase (26 Jun 1999) |
| beta-1,3-galactosyl-O-glycosyl-glycoprotein beta-1,6-acetylglucosaminyl transferase | <enzyme> With EC 2.4.1.148 this is called beta6-glcnac-transferase b Registry number: EC 2.4.1.102 Synonym: gal3-galnac-mucin-6-glcnac transferase, udp-glcnac-gal1-3galnac-r-(glcnac to galnac)-beta1-6glcnac transferase, core 2 glcnac transferase, core 2-n-acetylglucosaminyltransferase, core 2 beta6-gn-t (26 Jun 1999) |
| beta-1,4-mannosyl-glycoprotein beta-1,4-N-acetylglucosaminyltransferase | <enzyme> Induced in preneoplastic stage of liver carcinogenesis promoted by orotic acid in rats; adds "bisecting n-acetylglucosaminyl residue in beta 1,4 linkage to the beta-linked mannose of the core of asparagine-linked oligosaccharides Registry number: EC 2.4.1.144 Synonym: n-acetylglucosaminyltransferase III, udpgnac-glycopeptide beta4-n-acetylglucosaminyl transferase III, udpgnac-magtransferase III, udp-n-acetylglucosamine-beta-d-mannoside beta-1,4-n-acetylglucosaminyltransferase III (26 Jun 1999) |
| beta-hydroxy-beta-methylglutaryl-CoA | -OOCCH2C(OH)(CH3)CH2COS-CoA;a key intermediate in the synthesis of ketone bodies and of steroids. Synonym: 3-hydroxy-3-methylglutaryl-CoA. Beta-hydroxy-beta-methylglutaryl-lyase, an enzyme, found primarily in liver and rumen epithelium that catalyses the formation of acetyl-CoA and acetoacetate from beta-hydroxy-beta-methylglutaryl-CoA; a key step in ketogenesis; a deficiency of this enzyme leads to episodes of severe metabolic acidosis without ketosis. Beta-hydroxy-beta-methylglutaryl-reductase, an enzyme that catalyses the rate-limiting step of cholesterol biosynthesis, beta-hydroxy-beta-methylglutaryl-CoA + 2NADPH + 2H+ → mevalonate + 2NADP+ + coenzyme A. Beta-hydroxy-beta-methylglutaryl-synthase, an enzyme in mitochondria that catalyses the reaction of acetyl-CoA with acetoacetyl-CoA and water to form beta-hydroxy-beta-methylglutaryl-CoA and coenzyme A, a step required for both ketogenesis and steroidogenesis to occur. (05 Mar 2000) |
| beta-n-acetylglucosaminylglycopeptide beta-1,4-galactosyltransferase | <enzyme> An enzyme that catalyses the transfer of galactose from udp-galactose to a specific glycoprotein receptor, 2-acetamido-2-deoxy-d-glucosyl-glycopeptide, during glycopeptide synthesis. Chemical name: UDPgalactose:N-acetyl-beta-D-glucosaminylglycopeptide beta-1,4-galactosyltransferase Registry number: EC 2.4.1.38 (12 Dec 1998) |
| beta, or beta-value | <radiobiology> Ratio of plasma kinetic pressure to magnetic-field pressure, proportional to the ratio of plasma kinetic energy density to magnetic field energy density. Beta is usually measured relative to the total, local field (loosely called beta toroidal), but sometimes the plasma pressure relative to only the poloidal component of the field (beta poloidal) or relative to some external field (like the maximum field at the magnetic coils) is more useful. There is also a normalised beta (beta_N) of interest when discussing the beta limit. (lots of help from Art Carlson with the above.) Because the cost of a reactor is strongly influenced by the strength of the magnetic field that must be provided, beta values are directly related to the economics of fusion power production. Beta is usually expressed as a percentage, with 5% generally believed to be the minimum value required for an economical fusion reactor. See: pressure, kinetic pressure, magnetic pressure, second stability. (09 Oct 1997) |
| UDP-GalNAc-beta-galactose beta 1,4-N-acetylgalactosaminyltransferase | <enzyme> Consider also EC 2.4.1.92 Registry number: EC 2.4.1.- Synonym: beta-1,4-n-acetylgalactosaminyltransferase, 4-galnactransferase, udp-n-acetylgalactosamine-beta-galactose beta 1,4-n-acetylgalactosaminyltransferase, (1-4)-n-acetyl-beta-d-galactosaminyltransferase, galnact-1 (26 Jun 1999) |
| 5 alpha-androstane-3 beta,17 beta-diol 6 alpha-hydroxylase | <enzyme> Requires NADPH, found in rat prostatic microsomes Registry number: EC 1.14.13.- Synonym: artdl 6 alpha-hydroxylase (26 Jun 1999) |
| 5 alpha-androstane 3 beta,17 beta-diol 7 alpha-hydroxylase | <enzyme> Requires NADPH, found in rat prostate microsomes Registry number: EC 1.14.13.- Synonym: artdl 7 alpha-hydroxylase (26 Jun 1999) |
| A chain | A polypeptide component of insulin containing 21 amino acyl residues, beginning with a glycyl residue (NH2-terminus); insulin is formed by the linkage of an A chain to a B chain by two disulfide bonds; the amino-acid composition of the A chain is a function of species. Synonym: glycyl chain. In general, one of the polypeptides in a multiprotein complex. (05 Mar 2000) |
| alpha chain disease | A vague or indefinite term; could be used for alpha-heavy-chain disease (a lymphoplasma cell proliferative disease usually seen in Mediterranean men, characterised by intestinal involvement with steatorrhoea, often progressive with fatal outcome) or a thalassaemia (a genetic abnormality in the alpha globin chain of haemoglobin). (05 Mar 2000) |