YO-1 Synthesis and separation of peptide-oxidized phospholipid adducts, a potential lipoxidation marker

Oxidative stress has been linked to several inflammatory diseases, possibly due to oxidative damage to biomolecules. Recently, oxidized phospholipids have been shown to be related to several pathophysiological pathways through protein modification, creating protein-phospholipid adducts. The literature on protein-phospholipid adducts is sparse, thus the aim of this project is to study the formation of these adducts and to uncover potential biomarkers for disease, using different mass spectrometry techniques. The formation of phospholipid adducts was studied using human serum albumin, firstly reacting the whole protein with pentanal, a saturated aldehyde model of the fragmented chain of an oxidized phospholipid, and then reacting a synthetic HSA peptide, known to be susceptible to pentanal adduct formation, with the oxidized phosphatidylcholine PONPC. The reactions were analysed by LC-MS/MS and LC-MRM. This analysis showed mass shifts consistent with the formation of HSA-pentanal and peptide-PONPC Schiffu0027s base adducts located on the lysine residues. Different separation techniques have also been tested in order to develop an enrichment step. The new diagnostic ions and mass spectrometry approaches developed could be used to detect biomarkers for inflammatory diseases.