title: Carbonyl reduction in the biosynthesis of a male sex pheromone secreted by the grape borer Xylotrechus pyrrhoderus.
abstract: Males of the cerambycid beetle Xylotrechus pyrrhoderus release a mixture of (S)-2-hydroxy-3-octanone [(S)-1] and (2S,3S)-2,3-octanediol [(2S,3S)-2] as a sex pheromone that attracts conspecific females. The chemical structures of these pheromone components include a common motif and are assumed to be biosynthetically related. Here, we show that deuterated (S)-1, applied on the cuticle of a pronotal pheromone gland, was converted into (2S,3S)-2, that included deuterium atoms, but a reverse conversion did not take place. These results reveal a carbonyl reductase to be active in the pheromone gland, and that the ketol is a biosynthetic precursor of the diol. Males did not produce (R)-1; however, deuterated (R)-1 was converted into (2R,3R)-2, indicating an attack of the enzyme from the opposite side of the hydroxyl group at the 2-position. Furthermore, to understand the substrate specificity of the enzyme, racemates of 2-hydroxy-3-hexanone and 2-hydroxy-3-decanone were synthesized and applied to the gland. Their conversion into the corresponding diols suggests that the enzyme reduces the carbonyl group at the 3-position, regardless of the chain length.
authors.affiliation: Department of Applied Biological Science, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan.
authors.forename: Kikuo
authors.initials: K
authors.lastname: Iwabuchi
authors.forename: Maki
authors.initials: M
authors.lastname: Arakawa
authors.forename: Ryutaro
authors.initials: R
authors.lastname: Kiyota
authors.forename: Keita
authors.initials: K
authors.lastname: Hoshino
authors.forename: Tetsu
authors.initials: T
authors.lastname: Ando
mesh_terms: D000818:Animals; D001517:Coleoptera / Q000502:physiology*; D005260:Female; D007659:Ketones / Q000032:analysis / Q000378:metabolism; D008297:Male; D000442:Octanols / Q000032:analysis / Q000378:metabolism; D010084:Oxidation-Reduction; D012724:Sex Attractants / Q000032:analysis / Q000378:metabolism*; D027843:Vitis / Q000469:parasitology*
chemical_list: D007659:Ketones; D000442:Octanols; D012724:Sex Attractants; C535047:1,2-octanediol; C017582:3-octanone