Wadman Mayken W, van Zadelhoff Guus, Hamberg Mats, Visser Tom, Veldink Gerrit A, Vliegenthart Johannes F G
Department of Bio-organic Chemistry, Utrecht University, 3584-CH, Utrecht, The Netherlands.
Lipids. 2005 Nov;40(11):1163-70. doi: 10.1007/s11745-005-1481-2.
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.
氧脂类与真菌生命周期的重要过程相关，如孢子形成。在此，我们报道了双孢蘑菇中脂肪酸代谢产物的形成。用亚油酸（18:2）孵育菌褶粗提物导致两种氧脂类大量形成。通过反相高效液相色谱（RP-HPLC）、气相色谱-质谱联用（GC-MS）、红外光谱（IR）、非对映异构体衍生物的GC-MS分析以及1H核磁共振（1H NMR）和13C核磁共振（13C NMR）光谱，它们被鉴定为8(R)-羟基-9Z,12Z-十八碳二烯酸（8-HOD）和8(R),11(S)-二羟基-9Z,12Z-十八碳二烯酸（8,11-二HOD）。之前在双孢蘑菇中均未报道过这两种化合物。油酸（18:1）、α-亚麻酸（18:3n-3）和γ-亚麻酸（18:3n-6）也被转化为它们的8-羟基衍生物，并且18:3n-3进一步代谢为其8,11-二醇衍生物。用[U-13C]18:2进行的反应表明，8-HOD和8,11-二HOD是由外源供应的18:2形成的。当供应[U-13C]8-HOD时，它未转化为8,11-二HOD，这表明它不是8,11-二HOD形成过程中的中间体。当双孢蘑菇粗提物在16O2/18O2气氛中孵育时，8,11-二HOD的两个羟基要么含有两个18O原子，要么含有两个16O原子。无法检测到含有每种同位素各一个的物种。我们推测8,11-二羟基化合物的形成是通过8,11-内过氧、8-过氧自由基或8-氢过氧中间体进行的。在后一种情况下，该反应应由具有新特异性的双加氧酶催化。
