Albert C J, Crowley J R, Hsu F F, Thukkani A K, Ford D A
Department of Biochemistry and Molecular Biology, St. Louis University Health Sciences Center, St. Louis, Missouri 63104, USA.
J Biol Chem. 2001 Jun 29;276(26):23733-41. doi: 10.1074/jbc.M101447200. Epub 2001 Apr 11.
Plasmalogens contain a vinyl ether bond linking the sn-1 aliphatic chain to the glycerol backbone of this predominant phospholipid molecular subclass, which is found in many mammalian tissues. The present study demonstrates that the vinyl ether bond of plasmalogens is a molecular target of the reactive chlorinating species produced by myeloperoxidase. Analysis by thin layer chromatography revealed that reactive chlorinating species produced by myeloperoxidase target the vinyl ether bond of the plasmalogen, lysoplasmenylcholine (1-O-hexadec-1'-enyl-sn-glycero-3-phosphorylcholine), resulting in the production of a neutral lipid. Capillary gas chromatographic analyses demonstrated that the neutral lipid generated from lysoplasmenylcholine was neither hexadecanal nor did it contain masked hexadecanal (i.e. the vinyl ether) because the dimethyl acetal of hexadecanal produced by acid methanolysis derivatization was no longer present. Electrospray ionization mass spectrometry of the myeloperoxidase-generated neutral lipid product was consistent with the production of a 16-carbon fatty aldehyde containing one chlorine atom. Furthermore, proton NMR analysis indicated that this neutral lipid product was a 2-chloro-fatty aldehyde. Additional structural analysis of this neutral lipid by gas chromatography-mass spectrometry of the underivatized product as well as its pentafluorobenzyl oxime-derivative product was consistent with the neutral lipid being 2-chlorohexadecanal. The reactive chlorinating species, hypochlorous acid and chlorine gas, both attacked the vinyl ether bond of lysoplasmenylcholine resulting in the production of 2-chlorohexadecanal. The production of 2-chlorohexadecanal was dependent on the presence of the plasmalogen masked aldehyde (i.e. the vinyl ether) in the substrate because the free fatty aldehyde, hexadecanal, was not converted to 2-chlorohexadecanal by the reactive chlorinating species generated by myeloperoxidase. Taken together, the present studies demonstrate for the first time the targeting of the vinyl ether bond of plasmalogens by the reactive chlorinating species produced by myeloperoxidase resulting in the production of novel chlorinated fatty aldehydes.
缩醛磷脂含有一个乙烯基醚键，该键将sn-1脂肪链连接到这种主要磷脂分子亚类的甘油主链上，这种磷脂分子亚类存在于许多哺乳动物组织中。本研究表明，缩醛磷脂的乙烯基醚键是髓过氧化物酶产生的活性氯化物质的分子靶点。薄层色谱分析显示，髓过氧化物酶产生的活性氯化物质靶向缩醛磷脂溶血缩醛磷脂酰胆碱（1-O-十六碳-1'-烯基-sn-甘油-3-磷酸胆碱）的乙烯基醚键，从而产生一种中性脂质。毛细管气相色谱分析表明，由溶血缩醛磷脂酰胆碱产生的中性脂质既不是十六醛，也不含有被掩盖的十六醛（即乙烯基醚），因为酸甲醇解衍生化产生的十六醛二甲基缩醛不再存在。髓过氧化物酶产生的中性脂质产物的电喷雾电离质谱与含有一个氯原子的16碳脂肪醛的产生一致。此外，质子核磁共振分析表明，这种中性脂质产物是一种2-氯脂肪醛。通过对未衍生化产物及其五氟苄基肟衍生化产物进行气相色谱-质谱联用对该中性脂质进行的额外结构分析与该中性脂质为2-氯十六醛一致。活性氯化物质次氯酸和氯气均攻击溶血缩醛磷脂酰胆碱的乙烯基醚键，导致产生2-氯十六醛。2-氯十六醛的产生取决于底物中缩醛磷脂掩盖醛（即乙烯基醚）的存在，因为游离脂肪醛十六醛不会被髓过氧化物酶产生的活性氯化物质转化为2-氯十六醛。综上所述，本研究首次证明了髓过氧化物酶产生的活性氯化物质靶向缩醛磷脂的乙烯基醚键，从而产生新型氯化脂肪醛。
