title: Conversion of linoleic acid into novel oxylipins by the mushroom Agaricus bisporus.
abstract: Oxylipins are associated with important processes of the fungal life cycle, such as spore formation. Here, we report the formation of FA metabolites in Agaricus bisporus. Incubation of a crude extract of lamellae with linoleic acid (18:2) led to the extensive formation of two oxylipins. They were identified as 8(R)-hydroxy-9Z,12Z-octadecadienoic acid (8-HOD) and 8(R),11 (S)-dihydroxy-9Z,12Z-octadecadienoic acid (8,11-diHOD) by using RP-HPLC, GC-MS, IR, GC-MS analysis of diastereomeric derivatives, and 1H NMR and 13C NMR spectroscopy. Neither compound has been reported before in A. bisporus. Oleic (18:1), alpha-linolenic (18:3n-3), and gamma-linolenic (18:3n-6) acids were converted into their 8-hydroxy derivatives as well, and 18:3n-3 was further metabolized to its 8,11-diol derivative. Reactions with [U-13C]18:2 demonstrated that the compounds 8-HOD and 8,11-diHOD were formed from exogenously supplied 18:2. When [U-13C]8-HOD was supplied, it was not converted into 8,11-diHOD, indicating that it was not an intermediate in the formation of 8,11-diHOD. When a crude extract of A. bisporus was incubated under an atmosphere of 16O2/18O2, the two hydroxyl groups of 8,11-diHOD contained either two 180 atoms or two 60 atoms. Species that contained one of each isotope could not be detected. We propose that the formation of the 8,11-dihydroxy compounds occurs through either an 8,11-endoperoxy, an 8-peroxo free radical, or an 8-hydroperoxy intermediate. In the latter case, the reaction should be catalyzed by dioxygenase with novel specificity.
authors.affiliation: Department of Bio-organic Chemistry, Utrecht University, 3584-CH, Utrecht, The Netherlands.
authors.forename: Mayken W
authors.initials: MW
authors.lastname: Wadman
authors.forename: Guus
authors.initials: G
authors.lastname: van Zadelhoff
authors.forename: Mats
authors.initials: M
authors.lastname: Hamberg
authors.forename: Tom
authors.initials: T
authors.lastname: Visser
authors.forename: Gerrit A
authors.initials: GA
authors.lastname: Veldink
authors.forename: Johannes F G
authors.initials: JF
authors.lastname: Vliegenthart
mesh_terms: D000364:Agaricus / Q000201:enzymology / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis* / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D019787:Linoleic Acid / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D013055:Spectrophotometry, Infrared
chemical_list: D005231:Fatty Acids, Unsaturated; C027369:octadecadienoic acid; D019787:Linoleic Acid