| genes, T-cell receptor beta | DNA sequences encoding the beta chain of the T-cell receptor. The genomic organization of the tcr beta genes is essentially the same in all species and is similar to the organization of ig genes. (12 Dec 1998) |
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| receptors, adrenergic, beta | One of the two major pharmacologically defined classes of adrenergic receptors. The alpha-beta distinction was originally based on the cellular effects of receptor activation but now relies on the relative affinities for characteristic synthetic ligands. Beta adrenergic receptors are further subdivided based on information from endogenous and cloned receptors. (12 Dec 1998) |
| receptors, adrenergic, beta-1 | A subclass of beta-adrenergic receptors (receptors, adrenergic, beta). Beta-1 adrenergic receptors are equally sensitive to epinephrine and norepinephrine and bind the agonist dobutamine and the antagonist metoprolol with high affinity. They are found in the heart, juxtaglomerular cells, and in the central and peripheral nervous systems. (12 Dec 1998) |
| receptors, adrenergic, beta-2 | A subclass of beta-adrenergic receptors (receptors, adrenergic, beta). Beta-2 adrenergic receptors are more sensitive to epinephrine than to norepinephrine and have a high affinity for the agonist terbutaline. They are widespread, with clinically important roles in skeletal muscle, liver, and vascular, bronchial, gastrointestinal, and genitourinary smooth muscle. (12 Dec 1998) |
| receptors, antigen, T-cell, alpha-beta | T-cell receptors composed of CD3-associated alpha and beta polypeptide chains and expressed primarily in CD4+ or CD8+ T-cells. Unlike immunoglobulins, the alpha-beta T-cell receptors recognise antigens only when presented in association with major histocompatibility (MHC) molecules. (12 Dec 1998) |
| receptors, transforming growth factor beta | Cell-surface proteins that bind transforming growth factor beta and trigger changes influencing the behaviour of cells. Two types of transforming growth factor receptors have been recognised. They differ in affinity for different members of the transforming growth factor beta family and in cellular mechanisms of action. Transforming growth factor alpha binds to the same receptors as epidermal growth factor (see receptors, epidermal growth factor-urogastrone). (12 Dec 1998) |
| carotene, beta | An antioxidant which protects cells against oxidation damage that can lead to cancer. Beta-carotene is converted, as needed, to vitamin A. Food sources of beta carotene include vegetables such as carrots, sweet potatoes, spinach and other leafy green vegetables; and fruit such as cantaloupes and apricots. Excessive carotene in the diet can temporarily yellow the skin, a condition called carotenaemia, commonly seen in infants fed largely mushed carrots. (12 Dec 1998) |
| glucan 1,3-beta-glucosidase | <enzyme> Chemical name: exo-1,3-beta-glucanase Registry number: EC 3.2.1.58 Synonym: beta-(1-3)-glucanase, exoglucanase, 1,3-beta-glucanase, antiviral tobacco protein gp35, exo-1,3 beta-d-glucosidase, exg1 gene product, exoglucanase II, beta-1,3-glucanase (26 Jun 1999) |
| glucan endo-1,3-beta-d-glucosidase | <enzyme> An enzyme that hydrolyzes 1,3-beta-d-glucosidic linkages in 1,3-beta-d-glucans including laminarin, paramylon, and pachyman. Chemical name: 1,3-beta-D-Glucan glucanohydrolase Registry number: EC 3.2.1.39 (12 Dec 1998) |
| glucosaminylgalactosylglucosylceramide beta-galactosyltransferase | <enzyme> Attaches galactose in a beta 1-3 bond to form the tetrasaccharide-ceramide Registry number: EC 2.4.1.86 Synonym: lc3 galactosyltransferase, udp-galactose-lc3 galactosyltransferase, lactotriosylceramide galactosyltransferase, glcnac beta1-3 gal beta1-4 glc beta1-cer galactosyltransferase, lactatriaosylceramide beta 1-3-galactosyltransferase (26 Jun 1999) |
| glucosylceramide beta-1-4-galactosyltransferase | <enzyme> Catalyses the formation of lactosylceramide from glucosylceramide and udp galactose; also uses dihexosides as acceptor Registry number: EC 2.4.1.- Synonym: udpgalactose ceramide monohexoside galactosyltransferase, glccer galactosyltransferase, galt-2, udpgalactose-glucosylceramide beta-1-4-galactosyltransferase (26 Jun 1999) |
| medication, beta-blocker | Drugs that antagonise the action of adrenaline (a beta adrenergic substance) and relieve stress to the heart muscle. Beta-blockers are often used to slow the heart rate or lower the blood pressure. (12 Dec 1998) |
| glycine-rich beta-glycoprotein | <enzyme> A glycine-rich, heat-labile beta-glycoprotein found in blood. It is a proactivator of complement 3 in the alternate pathway of complement activation. Factor b is converted by factor d to c3 convertase. Registry number: EC 3.4.21.47 (12 Dec 1998) |
| glycine-rich beta-glycoproteinase | <enzyme> A serum protein which during the alternate pathway of complement activation converts the inactive properdin factor b to c3 convertase. Registry number: EC 3.4.21.46 (12 Dec 1998) |
| glycoprotein-N-acetylgalactosamine 3-beta-galactosyltransferase | <enzyme> Forms o-glycan core i; forms galactosyl beta 1,3-n-acetylgalactosaminide mucin Registry number: EC 2.4.1.122 Synonym: udp-galactose-n-acetylgalactosamine-alpha-r beta3-galactosyltransferase, glycoprotein-galnac-galactosyltransferase, gp galnac gal transferase, core I beta3-galactosyltransferase, galnac-1-o-ser or thr 1-3 galactosyltransferase, udp-gal-n-acetylgalactosaminide mucin-beta 1,3-galactosyltransferase, udpgal-nacgm-galactosyltransferase, udp-galactose-alpha-n-acetylgalactosaminide beta 3 galactosyltransferase (26 Jun 1999) |