title: Stereospecific biosynthesis of (9S,13S)-10-oxo-phytoenoic acid in young maize roots.
abstract: Profiling of oxylipins from young maize roots revealed complex patterns of products mainly originating from the combined actions of 9- and 13-lipoxygenases and allene oxide synthase (AOS). A distinctive feature was the high content of the cyclopentenone 10-oxo-11-phytoenoic acid (10-oxo-PEA). Incubations with [1-14C]linoleic acid led to the formation of the α-ketols 13-hydroxy-12-oxo-9-octadecenoic acid and 9-hydroxy-10-oxo-12-octadecenoic acid as well as the cyclopentenones 12-oxo-10-phytoenoic acid (12-oxo-PEA) and 10-oxo-PEA in a ratio of 10:2:1:3. Chiral phase radio-HPLC showed that the labeled 10-oxo-PEA was mainly (93%) due to the 9S,13S-enantiomer, whereas 12-oxo-PEA was racemic. Recombinant maize AOS CYP74A19 (ZmAOS2) converted linoleic acid 9(S)-hydroperoxide (9-HPOD) into an allene oxide, 9,10-epoxy-10,12-octadecadienoic acid (9,10-EOD), which did not undergo cyclization but was solely hydrolyzed into the α-ketol. A cyclase activity promoting the conversion of 9,10-EOD into (9S,13S)-10-oxo-PEA was detected in the 10(5)×g supernatant prepared by differential centrifugation of the maize root homogenate. The data obtained suggested the existence of a new type of allene oxide cyclase, which is active towards an allene oxide formed from a 9-lipoxygenase-derived hydroperoxide.
authors.affiliation: Kazan Institute of Biochemistry and Biophysics, Russian Academy of Sciences, P.O. Box 30, Kazan, 420111 Russia.
authors.forename: Anna V
authors.initials: AV
authors.lastname: Ogorodnikova
authors.affiliation: Kazan Institute of Biochemistry and Biophysics, Russian Academy of Sciences, P.O. Box 30, Kazan, 420111 Russia.
authors.forename: Svetlana S
authors.initials: SS
authors.lastname: Gorina
authors.affiliation: Kazan Institute of Biochemistry and Biophysics, Russian Academy of Sciences, P.O. Box 30, Kazan, 420111 Russia.
authors.forename: Lucia S
authors.initials: LS
authors.lastname: Mukhtarova
authors.affiliation: Kazan Institute of Biochemistry and Biophysics, Russian Academy of Sciences, P.O. Box 30, Kazan, 420111 Russia.
authors.forename: Fakhima K
authors.initials: FK
authors.lastname: Mukhitova
authors.affiliation: Kazan Institute of Biochemistry and Biophysics, Russian Academy of Sciences, P.O. Box 30, Kazan, 420111 Russia.
authors.forename: Yana Y
authors.initials: YY
authors.lastname: Toporkova
authors.affiliation: Division of Physiological Chemistry II, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-17177 Stockholm, Sweden.
authors.forename: Mats
authors.initials: M
authors.lastname: Hamberg
authors.affiliation: Kazan Institute of Biochemistry and Biophysics, Russian Academy of Sciences, P.O. Box 30, Kazan, 420111 Russia. Electronic address: grechkin@mail.kibb.ru.
authors.forename: Alexander N
authors.initials: AN
authors.lastname: Grechkin
mesh_terms: D002851:Chromatography, High Pressure Liquid; D003517:Cyclopentanes / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D019746:Intramolecular Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008041:Linoleic Acids / Q000378:metabolism; D050356:Lipid Metabolism; D008054:Lipid Peroxides / Q000378:metabolism; D008084:Lipoxygenase / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism*; D013237:Stereoisomerism; D003313:Zea mays / Q000235:genetics / Q000378:metabolism*
chemical_list: C526312:12-oxo-phytoenoic acid; C506899:9-hydroperoxy-10,12-octadecadienoic acid; D003517:Cyclopentanes; D005231:Fatty Acids, Unsaturated; D007527:Isoenzymes; D008041:Linoleic Acids; D008054:Lipid Peroxides; D010940:Plant Proteins; C117433:13-lipoxygenase; D008084:Lipoxygenase; D019746:Intramolecular Oxidoreductases; C021377:hydroperoxide isomerase
keywords: (9S,13S)-10-oxo-11-phytoenoic acid; Allene oxide synthase; Cyclase; Cyclopentenone; Maize (Zea mays L.) roots; Oxylipins