| beta-d-glucosidase | A glucohydrolase similar to alpha-d-glucosidase, but attacking beta-glucosides and releasing beta-d-glucose. Synonym: amygdalase, cellobiase, gentiobiase. (05 Mar 2000) |
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| beta-d-glucuronidase | <enzyme> An enzyme catalyzing the hydrolysis of various beta-d-glucuronides, liberating free d-glucuronic acid and an alcohol; a deficiency of this enzyme is associated with Sly syndrome. Synonym: glusulase, glycuronidase. (05 Mar 2000) |
| beta-d-glucuronidase deficiency | A rare deficiency of beta-d-glucuronidase; an autosomal recessive disorder with several allelic forms, characterised by abnormal mucopolysaccharide metabolism leading to progressive mental deterioration, splenic and hepatic enlargement, and dysostosis multiplex. Synonym: mucopolysaccharidase. (05 Mar 2000) |
| beta-D-mannosidase | <enzyme> Catalyses hydrolysis of terminal, non-reducing beta-d-mannose residues in beta-d-mannosides Registry number: EC 3.2.1.25 Synonym: mannanase, beta-mannosidase, mana gene product (26 Jun 1999) |
| beta-DNA | <molecular biology> The normal form of DNA found in organisms, which exists as a right-handed helix. (09 Oct 1997) |
| beta-d thalassaemia | Thalassaemia due to a gene that depresses synthesis of both beta-and d-globin chains by the chromosome bearing the abnormal gene. Heterozygous state: thalassaemia minor with Hb F comprising 5 to 30% of total haemoglobin but distributed unevenly among cells, Hb A2 reduced or normal. Homozygous state: moderate anaemia with only Hb F present, no Hb A or Hb A2. Synonym: F thalassaemia. (05 Mar 2000) |
| beta emission | <radiobiology> Form of nuclear decay where a neutron splits into a proton plus electron plus neutrino set. The proton stays in the nucleus but the electron (beta ray) is ejected. (09 Oct 1997) |
| beta-endorphin | <chemical> A peptide consisting of amino acid sequence 61-91 of the endogenous pituitary hormone beta-lipotropin. The first four amino acids show a common tetrapeptide sequence with methionine- and leucine enkephalin. The compound shows opiate-like activity. Injection of beta-endorphin induces a profound analgesia of the whole body for several hours. This action is reversed after administration of naloxone. Chemical name: beta-Endorphin (12 Dec 1998) |
| beta error | The statistical error (said to be of the second kind or type II) made in testing when it is concluded that something is negative when it really is positive. Beta error is often referred to as a false negative. (12 Dec 1998) |
| beta-farnesene | 7,11-Dimethyl-3-methylene-1,6,10-dodecatriene;one of the two isomers (trans) that occurs in the alarm pheromone of some aphids and also in various essential oils. (05 Mar 2000) |
| beta-farnesene synthase | <enzyme> Catalyses conversion of farnesyl diphosphate to beta-farnesene; genbank af024615 Registry number: EC 3.6.1.- (26 Jun 1999) |
| beta fibres | Nerve fibre's having conduction velocities of about 40 m/sec. (05 Mar 2000) |
| beta-fructofuranosidase | Beta-h-Fructosidase;an enzyme hydrolyzing beta-d-fructofuranosides and releasing free d-fructose; if the substrate is sucrose, the product is d-glucose plus d-fructose (invert sugar); invert sugar is more easily digestible than sucrose. Synonym: invertase, invertin, saccharase. (05 Mar 2000) |
| beta-galactanase | <enzyme> Appears around day 7 of embryo development of the mollusc pomacea sp; responsible for the degradation of acidic beta-galactan to galactose and di- and tri-galactosides; see also exo-1,4-beta-galactanase and endo-1,4-beta galactanase Registry number: EC 3.2.1.- (26 Jun 1999) |
| beta-galactosidase | <enzyme> A group of enzymes that catalyses the hydrolysis of terminal, non-reducing beta-d-galactose residues in beta-galactosides. Chemical name: beta-D-Galactoside galactohydrolase Registry number: EC 3.2.1.23 (12 Dec 1998) |