title: Geraniol dehydrogenase, the key enzyme in biosynthesis of the alarm pheromone, from the astigmatid mite Carpoglyphus lactis (Acari: Carpoglyphidae).
abstract: Geraniol dehydrogenase (GeDH), which plays an important role in the biosynthesis of neral, an alarm pheromone, was purified from the astigmatid mite Carpoglyphus lactis. The enzyme was obtained in an apparently homogeneous and active form after 1879-fold purification through seven steps of chromatography. Car. lactis GeDH was determined to be a monomer in its active form with a relative molecular mass of 42 800, which is a unique subunit structure in comparison with already established alcohol dehydrogenases. Car. lactis GeDH oxidized geraniol into geranial in the presence of NAD+. NADP+ was ineffective as a cofactor, suggesting that Car. lactis GeDH is an NAD+-dependent alcohol dehydrogenase. The optimal pH and temperature for geraniol oxidation were determined to be pH 9.0 and 25 degrees C, respectively. The Km values for geraniol and NAD+ were 51.0 microm and 59.5 microm, respectively. Car. lactis GeDH was shown to selectively oxidize geraniol, whereas its geometrical isomer, nerol, was inert as a substrate. The high specificity for geraniol suggests that Car. lactis GeDH specializes in the alarm pheromone biosynthesis of Car. lactis. Car. lactis GeDH is composed of 378 amino acids. Structurally, Car. lactis GeDH showed homology with zinc-dependent alcohol dehydrogenases found in mammals and a mosquito (36.6-37.6% identical), and the enzyme was considered to be a member of the medium-chain dehydrogenase/reductase family, in view of the highly conserved sequences of zinc-binding and NAD+-binding sites. Phylogenetic analyses indicate that Car. lactis GeDH could be categorized as a new class, different from other established alcohol dehydrogenases.
authors.affiliation: Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Japan. noge@email.arizona.edu
authors.forename: Koji
authors.initials: K
authors.lastname: Noge
authors.forename: Makiko
authors.initials: M
authors.lastname: Kato
authors.forename: Naoki
authors.initials: N
authors.lastname: Mori
authors.forename: Michihiko
authors.initials: M
authors.lastname: Kataoka
authors.forename: Chihiro
authors.initials: C
authors.lastname: Tanaka
authors.forename: Yuji
authors.initials: Y
authors.lastname: Yamasue
authors.forename: Ritsuo
authors.initials: R
authors.lastname: Nishida
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Kuwahara
mesh_terms: D000080462:Acyclic Monoterpenes; D000426:Alcohol Dehydrogenase / Q000737:chemistry; D000429:Alcohol Oxidoreductases / Q000737:chemistry* / Q000302:isolation & purification / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D007700:Kinetics; D008925:Mites; D008969:Molecular Sequence Data; D039821:Monoterpenes / Q000737:chemistry; D010088:Oxidoreductases / Q000737:chemistry* / Q000302:isolation & purification / Q000502:physiology*; D010100:Oxygen / Q000737:chemistry; D010675:Pheromones / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity; D013729:Terpenes / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry
chemical_list: D000080462:Acyclic Monoterpenes; D039821:Monoterpenes; D010675:Pheromones; D013729:Terpenes; D010088:Oxidoreductases; D000429:Alcohol Oxidoreductases; D000426:Alcohol Dehydrogenase; C529957:geraniol dehydrogenase, Carpoglyphus lactis; D015032:Zinc; C007836:geraniol; D010100:Oxygen; C007076:citral