| beta-n-acetylhexosaminidase | <enzyme> An enzyme hydrolyzing terminal non-reducing n-acetyl-d-hexosamine residues in n-acetyl-beta-d-hexosaminides. It acts on glucosides, galactosides, and several oligosaccharides. Hexosaminidase a cleaves gm2, ga2, globosides, and hexosamine oligosaccharides. Deficiency of this isoenzyme causes tay-sachs disease. Hexosaminidase b cleaves all the above substrates except gm2. A deficiency of both a and b causes sandhoff disease. The enzyme has also been used as a tumour marker to distinguish between malignant and benign disease. Chemical name: beta-N-Acetyl-D-hexosaminide N-acetylhexosaminohydrolase Registry number: EC 3.2.1.52 (12 Dec 1998) |
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| beta-naphthoflavone | <chemical> A polyaromatic hydrocarbon inducer of p4501a1 and p4501a2 cytochromes. (proc soc exp biol med 1994 dec:207(3):302-308) Pharmacological action: enzyme inhibitors. (12 Dec 1998) |
| beta-normal | <radiobiology> Beta-N, the normalised beta, is beta relative to the beta limit. (09 Oct 1997) |
| beta-oxidation | <biochemistry> The oxidative breakdown of fatty acids into acetyl-coenzyme A by repeated oxidation at the beta-carbon atom. Oxidation of the beta-carbon (carbon 3) of a fatty acid causes the formation of the beta-keto (beta-oxo) acid analog. This is of importance in fatty acid catabolism, the entire pathway for the catabolism of saturated fatty acids containing an even number of carbon atoms. Beta-oxidation is a part of this pathway and acetyl-CoA is a major product of this pathway. (05 Mar 2000) |
| beta-oxidation-condensation theory | <biochemistry> That the two carbon fragments split from the fatty acid molecule by beta-oxidation are converted to acetic acid and then condensed to acetoacetic acid. (05 Mar 2000) |
| beta-poloidal | <radiobiology> Beta-P is the same as the ordinary beta, except only the poloidal field is used in calculating the magnetic field pressure. Beta-P is greater than 1 in many modern tokamaks. (09 Oct 1997) |
| beta-sitosterol | Stigmast-5-en-3b-ol; (24R)-24-ethyl-5-cholesten-3b-ol;a phytosterol and anticholesteraemic. Synonym: cinchol. (05 Mar 2000) |
| beta-sulfinylpyruvic acid | <biochemistry> An intermediate product of l-cysteine catabolism in mammalian tissue. Structure: HO2S-CH2-CO-COOH (05 Mar 2000) |
| beta-thionase | <enzyme> A multifunctional pyridoxal phosphate enzyme. In the second stage of cysteine biosynthesis it catalyses the reaction of homocysteine with serine to form cystathionine with the elimination of water. Chemical name: L-Serine hydro-lyase (adding homocysteine) Registry number: EC 4.2.1.22 (12 Dec 1998) |
| beta-thromboglobulin | <haematology> A platelet-specific protein which is released when platelets aggregate. Elevated plasma levels have been reported after deep venous thrombosis, preeclampsia, myocardial infarction with mural thrombosis, and myeloproliferative disorders. Measurement of beta-thromboglobulin in biological fluids by radioimmunoassay is used for the diagnosis and assessment of progress of thromboembolic disorders. (12 Dec 1998) |
| beta-tocopherol | 5,8-Dimethyltocol;a lower homolog of alpha-tocopherol, that contains one less methyl group in the aromatic nucleus and is less active biologically; accompanies alpha-T and gamma-beta-tocopherol (05 Mar 2000) |
| beta-tyrosinase | <enzyme> An enzyme that catalyses the cleavage of tyrosine to phenol, pyruvate, and ammonia. It is a pyridoxal phosphate protein. The enzyme also forms pyruvate from d-tyrosine, l-cysteine, s-methyl-l-cysteine, l-serine, and d-serine, although at a slower rate. Chemical name: L-Tyrosine phenol-lyase (deaminating) Registry number: EC 4.1.99.2 (12 Dec 1998) |
| beta-ureidopropionase | <enzyme> Chemical name: n-carbamoyl-beta-alanine amidohydrolase Registry number: EC 3.5.1.6 Synonym: n-carbamoyl beta-alanine amidohydrolase (26 Jun 1999) |
| betacism | A defect in speech in which the sound of b is given to other consonants. Origin: G. Beta, the second letter of the alphabet (05 Mar 2000) |
| betacyanin | One of several red plant pigments; a betalain. An example is betanin. Elevated in urine of individuals with beeturia. Origin: L. Beta, beet, + G. Kyanos, dark blue substance, + -in (05 Mar 2000) |
| exo-1,4-beta-galactanase | <enzyme> From bacillus subtilis; hydrolyzes soybean arabinogalactan to yield galactobiose and small amounts of galactotetrose Registry number: EC 3.2.1.- Synonym: arabinogalactan 4-beta-d-galactanohydrolase (26 Jun 1999) |
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| exo-1,4-beta-mannanase | <enzyme> From aeromonas hydrophila subsp. Anaerogenes Registry number: EC 3.2.1.- Synonym: 1,4-beta-d-mannan mannobiohydrolase (26 Jun 1999) |
| exo-beta-(1--3)-D-galactanase | <enzyme> From irpex lacteus (polyporus tulipferae); hydrolyzes specifically oligosaccharides and polymers of (1--3)-linked beta-d-galactopyranosyl residues; maximal activity exhibited at pH 4.6 Registry number: EC 3.2.1.- Synonym: ebd-galactanase, exo-(1-3)-galactanase (26 Jun 1999) |
| exo-beta-1,4-glucanase | <enzyme> Releases single glucose units from 1,4-beta-d-glucans; for release of cellobiose (disaccharide) units see exo-cellobiohydrolase, EC 3.2.1.91 Registry number: EC 3.2.1.74 Synonym: exo-1,4-beta-glucosidase, beta-(1-4)-glucanase, 1,4-beta-d-glucan glucohydrolase, glucan 1,4-beta-glucosidase (26 Jun 1999) |
| exo-beta-D-galactofuranosidase | <enzyme> Catalyses release of galactose from methyl and ethyl-beta-d-galactofuranosides, from 6-o-beta-galactofuranosyl-d-galactose and 5-o-beta-galactofuranosyl-containing peptidophosphogalactomannan from p. Charlesii culture filtrates Registry number: EC 3.2.1.- Synonym: beta-galactofuranosidase (26 Jun 1999) |
| exo-beta-D-glucosaminidase | <enzyme> Capable of hydrolyzing chitobiose; from culture filtrate of nocardia orientalis ifo 12806; exo-hydrolase, removing single glucosamine residues from the nonreducing terminal of a sequence of beta-(1--4)-linked glucosamine chain, such as chitosan and chitooligosaccharides; does not act on acetylated substrates or aryl-beta-glycosides Registry number: EC 3.2.1.- (26 Jun 1999) |
| tyramine beta-hydroxylase | <enzyme> This enzyme is dopamine beta-hydroxylase in mammals, but is a different enzyme in lobsters Registry number: EC 1.14.- (26 Jun 1999) |
| UDP-acetylglucosamine-beta-D-galactosylsaccharide acetylglucosaminyltransferase | <enzyme> Transfers 2-acetamido-2-deoxy-d-glucose from udp-2-acetamido-2-deoxy-d-glucose to terminal nonreducing beta-d-galactosyl residues in disaccharides, oligosaccharides, glycoproteins and glycolipids; detected in human serum Registry number: EC 2.4.1.- Synonym: udp-acetylglucosamine beta-d-galactosyl(1-4)saccharide (1-3)acetylglucosaminyltransferase, udp-agagt (26 Jun 1999) |
| UDP-beta(1-6)-D-galactosyltransferase | <enzyme> Catalyses transfer of d-galactose from udp-galactose to a (1-6) linkage on receptor h pomatia galactogen; beef lung galactogen, lymnaea stagnalis galactogen and arabinogalactan can also serve as receptors Registry number: EC 2.4.1.- Synonym: udp-d-galactosyltransferase beta (1-6), udp-galtransferase (1-6) (26 Jun 1999) |
| UDP-D-xylose-beta-D-glucoside alpha-1,3-xylosyltransferase | <enzyme> Catalyses transfer of xylose from udp-d-xylose to glucose Registry number: EC 2.4.2.- Synonym: udp-xyl-glc axt, beta-glucoside alpha-1,3-xylosyltransferase (26 Jun 1999) |
| UDP-galactose 4-O-beta-D-galactosyl-D-xylose galactosyltransferase | <enzyme> Involved in chondroitin sulfate synthesis Registry number: EC 2.4.1.- (26 Jun 1999) |
| UDP-galactose-lactosylceramide beta 1-3-galactosyltransferase | <enzyme> Catalyses transfer of galactose from udp-galactose to lactose or lactosylceramide Registry number: EC 2.4.1.- Synonym: udp-galactose-lactose beta 1-3 galactosyltransferase, udp-galactose-lactose (lactosylceramide) beta-3-galactosyltransferase, udpgal-lac-3-transferase (26 Jun 1999) |
| UDP-Gal-beta-galactoside beta1-3-galactosyltransferase | <enzyme> From lymnaea stagnalis; involved in galactogen biosynthesis Registry number: EC 2.4.1.- Synonym: udpgal-3-galactosyltransferase (26 Jun 1999) |
| UDP-GalNAc - GlcNAc beta-1,4-N-acetylgalactosaminyltransferase | <enzyme> Transfers galnac from donor udp-galnac to terminal glcnac residues in n-linked oligosaccharides Registry number: EC 2.4.1.- Synonym: beta-1,4-galnact (26 Jun 1999) |
| UDP-glucose LOS-beta-1,4-glucosyltransferase | <enzyme> Required for biosynthesis of lipooligosaccharide inner core extension in neisseria meningitidis; genbank u58765 Registry number: EC 2.4.1.- Synonym: lgtf gene product (26 Jun 1999) |