title: Identification of free radicals in oxidized and glycoxidized phosphatidylethanolamines by spin trapping combined with tandem mass spectrometry.
abstract: BACKGROUND
  Nonenzymatic glycation of phosphatidylethanolamines (PEs) seems to a have a role in angiogenesis and atherosclerosis. Glycated PEs are more easily oxidized, enhancing oxidative stress. This study aims to evaluate the influence of glycation on the formation of intermediate radical species during oxidation of glycated PEs.
  
  
  METHODS
  In the present study, the radical intermediaries formed during the oxidation of palmitoyl-lineoyl phosphatidylethanolamine (PLPE) and glycated PLPE (gPLPE) were trapped using a spin trap (DMPO) and the radical adducts were analyzed by electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS/MS). Mass spectra were acquired using a electrospray Q-TOF 2 mass spectrometer.
  
  
  RESULTS
  Several spin adducts of PLPE and gPLPE were identified, corresponding to carbon- and oxygen-centered radicals. Interpretation of the MS/MS spectra showed the existence of different sites where radical formation occurred, at the sn-2 acyl chain, ethanolamine moiety (particularly in C-1) and, in the case of glycated derivatives, also in the glucose moiety (particularly in C-3, C-4 and C-5).
  
  
  CONCLUSIONS
  These results suggested the presence of more sites susceptible to oxidation in glycated PLPE, which may be responsible for the increase in the oxidative reaction rate occurring in glycated compounds.
authors.affiliation: Mass Spectrometry Center, QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Cláudia
authors.initials: C
authors.lastname: Simões
authors.forename: Pedro
authors.initials: P
authors.lastname: Domingues
authors.forename: Maria Rosario M
authors.initials: MR
authors.lastname: Domingues
mesh_terms: D005609:Free Radicals / Q000737:chemistry*; D006031:Glycosylation; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010714:Phosphatidylethanolamines / Q000737:chemistry*; D019097:Spin Trapping / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D005609:Free Radicals; D010714:Phosphatidylethanolamines