title: A simple and efficient system for green note compound biogenesis by use of certain lipoxygenase and hydroperoxide lyase sources.
abstract: Six-carbon (C(6)) aldehydes and alcohols are important components of the aroma and flavor of fruits and vegetables. Soybean lipoxygenase (LOX) isozyme LOX 3 was reported not only to produce less 13-hydroperoxides, precursors of C(6) aldehydes, but also to convert them to ketodiene products. Here, we examined the effects of LOX 3 on hexenal formation from linolenic acid homogenized with watermelon 13-hydroperoxide lyase (HL)-overexpressing Nicotiana tabacum leaves and soybean acetone powder. Compared to the wild type, which contains LOXs 1, 2, and 3, the elimination of LOX 3 in LOX 1 + 2 facilitates greater production of hexenals. The use of LOX 2 alone yielded the highest hexenal production, while a two-step conversion was required for LOX 1 to produce hexenals at high levels due to different pH optima of the enzymes involved. These results clearly demonstrate that the soybeans lacking LOX 3 in combination with watermelon HL-overexpressing leaf tissues greatly enhance hexenal formation.
authors.affiliation: Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546, USA.
authors.forename: Hirotada
authors.initials: H
authors.lastname: Fukushige
authors.forename: David F
authors.initials: DF
authors.lastname: Hildebrand
mesh_terms: D000438:Alcohols / Q000032:analysis; D000446:Aldehyde-Lyases / Q000235:genetics / Q000378:metabolism*; D000447:Aldehydes / Q000032:analysis; D029773:Citrullus / Q000201:enzymology / Q000235:genetics; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D006591:Hexobarbital / Q000378:metabolism*; D008084:Lipoxygenase / Q000378:metabolism*; D009812:Odorants / Q000032:analysis*; D018515:Plant Leaves / Q000201:enzymology; D011994:Recombinant Proteins; D013025:Glycine max / Q000201:enzymology; D014026:Nicotiana / Q000201:enzymology; D017962:alpha-Linolenic Acid / Q000378:metabolism
chemical_list: D000438:Alcohols; D000447:Aldehydes; D011994:Recombinant Proteins; D017962:alpha-Linolenic Acid; D003577:Cytochrome P-450 Enzyme System; D006591:Hexobarbital; C095864:lipoxygenase 3; D008084:Lipoxygenase; D000446:Aldehyde-Lyases; C054540:hydroperoxide lyase