| 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) |
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| beta-galactoside alpha-2,3-sialyltransferase | <enzyme> Transfers sialic acid residue from cmp-n-acetylneuraminic acid to an acceptor galactoside Registry number: EC 2.4.99.4 Synonym: alpha 2-3-sialyltransferase, cmp-neuac-galactoside (alpha 2-3)-sialyltransferase, cmp-angs-transferase, cmp n-acetylneuraminate-beta-galactoside alpha-2,3-sialyltransferase, cmpsialic acid beta-galactosyl-1-3-n-acetylgalactosaminide alpha 2-3-sialyltransferase, beta-d-galactoside 3-alpha-sialyltransferase, cmp-acetylneuraminate-galactoside (alpha 2-3)-sialyltransferase, asialofetuin sialyltransferase, gal beta1,3galnac alpha2,3-sialyltransferase, cmp-neu5ac-gal beta1-3galnac alpha-2,3-sialyltransferase, cmp-neu5ac-gal1-3galnac alpha-2,3-sialyltransferase, alpha-2,3-st(o) (26 Jun 1999) |
| beta-galactoside permease | <chemical> Chemical name: permease, beta-galactoside (26 Jun 1999) |
| beta-galactosyl(1-3)N-acetylglucosaminide alpha(2-3)-sialyltransferase | <enzyme> Found in rat liver golgi apparatus Registry number: EC 2.4.99.- Synonym: gal-1-3-glcnac-sialyltransferase (26 Jun 1999) |
| beta-galactosylceramidase | <enzyme> An enzyme that participates in the catabolism of certain ceramides; a deficiency of beta-galactosylceramidase is associated with Krabbe's disease. (05 Mar 2000) |
| beta-globulins | The serum globulins with an electrophoretic mobility in neutral or alkaline solutions intermediate between that of alpha-globulins and gamma-globulins. (12 Dec 1998) |
| beta-glucocerebrosidase | <enzyme> An enzyme that hydrolyzes beta-glucosides in cerebrosides; a deficiency of this enzyme results in Gaucher disease. (05 Mar 2000) |
| beta-glucosidase | <enzyme> An enzyme that catalyses the hydrolysis of terminal non-reducing residues in beta-d-glucosides with release of beta-glucose. Chemical name: beta-D-Glucoside glucohydrolase Registry number: EC 3.2.1.21 (12 Dec 1998) |
| beta-glucosyl-hydroxymethylcytosine-alpha-glucosyltransferase | <enzyme> Generates gentobiosyl groups on the hydroxymethylcytosine of phage t2 and t6 DNA Registry number: EC 2.4.1.- Synonym: b-glc-hmc-a-glucosyltransferase (26 Jun 1999) |
| beta-haemolytic streptococci | Those that produce active haemolysins (O and S) which cause a zone of clear haemolysis on the blood agar medium in the area of the colony; beta-haemolytic streptococci are divided into groups (A to O) on the basis of cell wall C carbohydrate (see Lancefield classification); Group A (in the strains pathogenic for man) comprises more than 50 types (designated by Arabic numerals) determined by cell wall M protein, which seems to be associated closely with virulence and is produced chiefly by strains with matt or mucoid colonies, in contrast to nonvirulent, glossy colony-producing strains; other surface protein antigens such as R and T (T substance), and the nucleoprotein fraction (P substance) seem to be of less importance. The more than 20 extracellular substances elaborated by strains of beta-haemolytic streptococci include erythrogenic toxin (elaborated only by lysogenic strains), deoxyribonuclease (streptodornase), haemolysins (streptolysins O and S), hyaluronidase, and streptokinase. Synonym: haemolytic streptococci. (05 Mar 2000) |
| 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-hydroxyacyl-(acyl-carrier-protein)dehydrase | <enzyme> In fatty acid synthesis; specific for acyl carrier protein; cannot use acyl CoA; see also faba gene product Registry number: EC 4.2.1.- Synonym: beta-ohacyl-acp dehydrase, beta-hydroxyacyl-acyl carrier protein dehydratase, fabz gene product (26 Jun 1999) |
| beta-hydroxybutyric acid | CH3CH(OH)CH2COOH;the d-stereoisomer is one of the ketone bodies and is formed in ketogenesis; it is an important fuel for extrahepatic tissues; as an acyl derivative it is also an intermediate in fatty acid biosynthesis. The l-isomer is found as a coenzyme A derivative in b oxidation of fatty acids. Synonym: 3-hydroxybutanoic acid, beta-hydroxybutyric acid. D-3-hydroxybutyric acid dehydrogenase, an enzyme that reversibly catalyses the interconversion of the two main ketone bodies, catalyzing acetoacetate + NADH + H+ &dblarr; d-3-hydroxybutyrate + NAD+. (05 Mar 2000) |
| beta-hydroxyisobutyric acid | HOCH2CH(CH3)COOH;an intermediate in the degradation of l-valine. (05 Mar 2000) |
| beta-hydroxypropionic acid | A minor intermediate in propionate and methylmalonate metabolism. See: beta-hydroxypropionic aciduria. (05 Mar 2000) |