title: A highly specific D-hydroxyisovalerate dehydrogenase from the enniatin producer Fusarium sambucinum.
abstract: A highly specific D-hydroxyisovalerate (D-HIV) dehydrogenase, which is a key enzyme in depsipeptide synthesis, was purified to near homogeneity from the enniatin-producing fungus Fusarium sambucinum. The enzyme catalyzes the reversible reaction of 2-ketoisovalerate (2-KIV) to D-HIV. It is strictly dependent on NADPH and exhibits a high substrate specificity with respect to 2-KIV. NADH was not accepted by the enzyme. Km values for 2-KIV and NADPH were found to be 200 and 333 microM, respectively. D-HIV dehydrogenase consists of a single polypeptide chain with a molecular mass of about 53 kDa. Optimum temperature for the reduction of 2-KIV was 35 degrees C and for the oxidation reaction was 45 degrees C. The optimum pH was found to be 7 for the reduction and 8-9 for the oxidation reaction.
authors.affiliation: Institut für Biochemie und Molekulare Biologie, Technischen Universität Berlin, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Lee
authors.forename: H
authors.initials: H
authors.lastname: Görisch
authors.forename: H
authors.initials: H
authors.lastname: Kleinkauf
authors.forename: R
authors.initials: R
authors.lastname: Zocher
mesh_terms: D000429:Alcohol Oxidoreductases / Q000302:isolation & purification* / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000096:biosynthesis; D001345:Autoradiography; D002384:Catalysis; D002850:Chromatography, Gel; D047630:Depsipeptides; D004591:Electrophoresis, Polyacrylamide Gel; D005670:Fusarium / Q000201:enzymology* / Q000254:growth & development; D045782:Hemiterpenes; D006863:Hydrogen-Ion Concentration; D007651:Keto Acids / Q000378:metabolism; D007700:Kinetics; D008970:Molecular Weight; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D010453:Peptide Synthases / Q000378:metabolism; D010455:Peptides; D010456:Peptides, Cyclic / Q000096:biosynthesis; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D000900:Anti-Bacterial Agents; D047630:Depsipeptides; D045782:Hemiterpenes; D007651:Keto Acids; D010455:Peptides; D010456:Peptides, Cyclic; C100264:enniatins; D009243:NAD; D009249:NADP; C001505:alpha-ketoisovalerate; D000429:Alcohol Oxidoreductases; C075121:hydroxyisovalerate dehydrogenase; D010453:Peptide Synthases; C023122:enniatin B synthetase