Liquid chromatography-tandem mass spectrometry of phosphatidylserine advanced glycated end products

Phosphatidylserine (PS) is an aminophospholipid that is prone to glycation. In oxidative conditions, glycated PS may lead to the formation of Amadori compounds and advanced glycated end products (AGEs), which are known to accumulate in diabetic patients. Nevertheless, there have been no studies that identified products from the oxidative reaction of glycated PS. In this study, glycated 1-palmitoyl-2-oleoyl-PS was synthesized and further oxidized by Fenton reagent. The AGES formed were structurally characterized by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in negative mode. The oxidation products from glycated PS that we have found include products arising from the oxidation of the fatty acyl chains (hydroperoxides, hydroxides and keto derivatives), and arising from oxidative cleavage of serine polar head and lyso-glycated PS. Oxidation in C6 of glucose lead to the formation of glucuronyl-PS. In addition, new products arising from oxidative cleavage of glucose moiety (between C1C2, C2C3 and C3C4 bonds) were identified as PS-AGES. The current findings add substantially to the best of our knowledge of PS glycoxidation products, opening new perspectives for the detection of these products in complex biological matrices.