| beta-adrenoreceptor antagonist | A class of drugs that compete with beta-adrenergic agonists for available receptor sites; some compete for both b1 and b2 receptors (e.g., propranolol) while others are primarily either b1 (e.g., metoprolol) or b2 blockers; used in the treatment of a variety of cardiovascular diseases where beta-adrenergic blockade is desirable. Synonym: beta-adrenergic receptor blocking agent, beta-adrenoreceptor antagonist, beta-blocker. (05 Mar 2000) |
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| beta-alanine | <chemical> Beta-alanine. An amino acid formed in vivo by the degradation of dihydrouracil and carnosine. Since neuronal uptake and neuronal receptor sensitivity to beta-alanine have been demonstrated, the compound may be a false transmitter replacing gaba. A rare genetic disorder, hyper-beta-alaninaemia, has been reported. Chemical name: beta-Alanine (12 Dec 1998) |
| beta-alanine-pyruvate aminotransferase | <enzyme> An enzyme that reversibly transfers the amino group of beta-alanine to paruvate, thus producing l-alanine and malonate saemialdehyde. A deficiency of this enzyme is believed to be the cause of hyper-beta-alaninaemia. (05 Mar 2000) |
| beta-alanyl-arginine hydrolase | <enzyme> Also hydrolyzes carnosine, at a lower rate; requires mn2+; inhibited by bestatin; stabilised by sulfhydryl reagents Registry number: EC 3.4.13.- Synonym: ala-arg hydrolase (26 Jun 1999) |
| beta alcoholism | Jellinek's term for the physical complaints associated with excessive use of alcohol, such as polyneuropathy, gastritis, and liver cirrhosis. (05 Mar 2000) |
| beta-allocortol | 5alpha-Pregnane-3a,11b,17,20b,21-pentaol;the 20b isomer of alpha-allocortol and 5a enantiomer of beta-cortol; a metabolite of hydrocortisone found in urine. (05 Mar 2000) |
| beta-allocortolone | 3a,17,20b,21-Tetrahydroxy-5alpha-pregnane-11-one;the 20b isomer of alpha-allocortolone and 5a enantiomer of beta-cortolone; a metabolite of hydrocortisone found in urine. (05 Mar 2000) |
| beta-allopregnanediol | The 5alpha-pregnane-3b,20a(and b)-diols; both are metabolites of progesterone and adrenocortical hormones; found in urine. (05 Mar 2000) |
| beta-aminoisobutyrate:pyruvate aminotransferase | Beta-aminosiobutyrate:pyruvate transaminase;an enzyme that catalyses the reversible transfer of an amino group from beta-aminoisobutyrate to pyruvate, producing l-alanine and methylmalonate saemialdehyde. A step in valine degradation. A deficiency of beta-aminoisobutyrate:pyruvate aminotransferase results in hyper-beta-aminoisobutyric aciduria. (05 Mar 2000) |
| beta-aminoisobutyric acid | 3-Amino-2-methylpropionic acid;an end product of thymine catabolism; high urinary levels (200-300 mg/day) have been noted in some individuals, either from some disease process or following a genetic pattern. (05 Mar 2000) |
| beta-aminoisobutyric acid oxidase | <enzyme> Fad-stimulated, probably forms methylmalonylsaemialdehyde Registry number: EC 1.4.3.- Synonym: baib-oxidase (26 Jun 1999) |
| beta-amylase | <enzyme> An enzyme that catalyses the hydrolysis of 1,4-alpha-glycosidic linkages in starch, glycogen, and related polysaccharides and oligosaccharides so as to remove successive beta-maltose units from the non-reducing ends of the chains. Chemical name: 1,4-alpha-D-Glucan maltohydrolase Registry number: EC 3.2.1.2 (12 Dec 1998) |
| beta-amyloid | <protein> The protein which forms thick deposits, or plaques, in the brains of people with Alzheimer's disease, a disease where memory skills gradually deteriorate with age. (13 Nov 1997) |
| beta angle | The angle formed by a line connecting the bregma and hormion meeting the radius fixus. (05 Mar 2000) |
| beta-aspartyl(acetylglucosamine) | Misnomer for 1-(beta-asparagino)-N-acetylglucosamine or 1-(beta-aspartamido)-N-acetylglucosamine, or, formally, 1-(beta-l-aspartamido)-N-2-acetamido-1,2-dideoxy-beta-d-glucose; a compound of N-acetylglucosamine and asparagine, linked via the amide nitrogen of the latter and carbon-1 of the former. An important structural linkage in many glycoproteins. (05 Mar 2000) |