title: Allene oxide synthases and allene oxides.
abstract: Allene oxides are unstable epoxides formed by the enzymatic dehydration of the lipoxygenase products of polyunsaturated fatty acids. The allene oxide synthases are of two structurally-unrelated types. In plants, a subfamily of cytochromes P450, designated as CYP74A, use the hydroperoxides of linoleic and linolenic acids as substrate. Both the 9- and 13-hydroperoxides may be converted to allene oxides and subsequently give rise to plant signaling molecules. In corals, a catalase-related hemoprotein functions as the allene oxide synthase. These marine invertebrates, as well as starfish, form allene oxides from the 8R-hydroperoxide of arachidonic acid. The coral allene oxide synthase from Plexaura homomalla occurs as the N-terminal domain of a natural fusion protein with the 8R-lipoxygenase that forms its substrate. This enzyme may be involved in biosynthesis of the cyclopentenone eicosanoids such as the clavulones.
authors.affiliation: Department of Pharmacology, Vanderbilt University Medical School, Nashville, TN 37232-6602, USA.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Tijet
authors.forename: Alan R
authors.initials: AR
authors.lastname: Brash
mesh_terms: D000466:Alkadienes / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D037421:Anthozoa / Q000201:enzymology; D016718:Arachidonic Acid / Q000378:metabolism; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000378:metabolism*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000378:metabolism; D016415:Sequence Alignment; D015398:Signal Transduction / Q000502:physiology
chemical_list: D000466:Alkadienes; D010940:Plant Proteins; D016718:Arachidonic Acid; C025947:propadiene; D019746:Intramolecular Oxidoreductases; C021377:hydroperoxide isomerase