title: 2-Hydroxyacid dehydrogenase from Haloferax mediterranei, a D-isomer-specific member of the 2-hydroxyacid dehydrogenase family.
abstract: An NAD-dependent D-2-hydroxyacid dehydrogenase (EC 1.1.1.) was isolated and characterized from the halophilic Archaeon Haloferax mediterranei. The enzyme is a dimer with a molecular mass of 101.4 +/- 3.3 kDa. It is strictly NAD-dependent and exhibits its highest activity in 4 M NaCl. The enzyme is characterized by a broad substrate specificity 2-ketoisocaproate and 2-ketobutyrate being the substrates with the higher Vmax/Km. When pyruvate and 2-ketobutyrate were the substrates the optimal pH was acidic (pH 5) meanwhile for 2-ketoisocaproate maximum activity was achieved at basic pH between 7.5 and 8.5. The optimum temperature was 52 degrees C and at 65 degrees C there was a pronounced activity decrease. This new enzyme can be used for the production of D-2-hydroxycarboxylic acid.
authors: Departamento de Bioquímica, Facultad de Ciencias, Universidad de Alicante, Ap. 99, Alicante, Spain. mjbonete@ua.es
authors: M J
authors: MJ
authors: Bonete
authors: J
authors: J
authors: Ferrer
authors: C
authors: C
authors: Pire
authors: M
authors: M
authors: Penades
authors: J L
authors: JL
authors: Ruiz
mesh_terms: D000429:Alcohol Oxidoreductases / Q000187:drug effects / Q000302:isolation & purification* / Q000378:metabolism*; D002264:Carboxylic Acids / Q000378:metabolism; D004795:Enzyme Stability / Q000187:drug effects; D019623:Haloferax mediterranei / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes; D007651:Keto Acids / Q000378:metabolism*; D007700:Kinetics; D013058:Mass Spectrometry / Q000379:methods; D015394:Molecular Structure; D008970:Molecular Weight; D012492:Salts / Q000494:pharmacology; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D002264:Carboxylic Acids; D007527:Isoenzymes; D007651:Keto Acids; D012492:Salts; D000429:Alcohol Oxidoreductases; C083779:2-hydroxyacid dehydrogenase