title: Identification of 1-palmitoyl-2-linoleoyl-phosphatidylethanolamine modifications under oxidative stress conditions by LC-MS/MS.
abstract: Phosphatidylethanolamines are a major class of phospholipids found in cellular membranes. Identification of the alterations in these phospholipids, induced by free radicals, could provide new tools for in vivo diagnosis of oxidative stress. In this study, 1-palmitoyl-2-linoleoyl-phosphatidylethanolamine oxidation products, induced by the hydroxyl radical, were studied using LC-MS and LC-MS/MS. Data obtained allowed the identification and separation of isomeric oxidative products with modifications in the sn-2 acyl chain, attributed to long- and short-chain products. Among long-chain products keto, keto-hydroxy, hydroxy, poly-hydroxy, peroxy and hydroxy-peroxy derivatives were identified. Product ions formed by loss of two H2O molecules vs loss of HOOH, allowed the identification of, respectively, di- (or poli-) hydroxy vs peroxy derivatives. Location of functional groups was determined by the product ions formed by cleavage of C-C bonds, in the vicinity of the oxidation positions, allowing the identification of C9, C12 and C13 as the predominant substituted positions. Short-chain products identified comprised aldehydes, hydroxy-aldehydes and carboxylic derivatives, with modified sn-2 acyl lengths of C7-C9 and C11, C12. Among the short-chain products identified, C9 products showed higher relative abundance.
authors.affiliation: Mass Spectrometry Centre, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal. mrd@ua.pt
authors.forename: M Rosário M
authors.initials: MR
authors.lastname: Domingues
authors.forename: Cláudia
authors.initials: C
authors.lastname: Simões
authors.forename: João Pinto
authors.initials: JP
authors.lastname: da Costa
authors.forename: Ana
authors.initials: A
authors.lastname: Reis
authors.forename: Pedro
authors.initials: P
authors.lastname: Domingues
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D017665:Hydroxyl Radical / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010714:Phosphatidylethanolamines / Q000032:analysis* / Q000737:chemistry; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D010714:Phosphatidylethanolamines; C052154:1-palmitoyl-2-linoleoyl-3-phosphatidylethanolamine; D017665:Hydroxyl Radical