Mass Spectrometry Centre, UI QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
Chem Phys Lipids. 2013 Sep;174:1-7. doi: 10.1016/j.chemphyslip.2013.05.005. Epub 2013 Jun 14.
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.
磷脂酰丝氨酸（PS）是一种易糖化的氨基磷脂。在氧化条件下，糖化 PS 可能导致 Amadori 化合物和晚期糖基化终产物（AGEs）的形成，已知这些物质在糖尿病患者中会积累。然而，目前还没有研究鉴定出糖化 PS 氧化反应的产物。在这项研究中，合成了糖化 1-棕榈酰-2-油酰-PS，并用 Fenton 试剂进一步氧化。通过液相色谱-串联质谱（LC-MS/MS）在负离子模式下对形成的 AGEs 进行了结构表征。我们发现，糖化 PS 的氧化产物包括来自脂肪酸链氧化的产物（氢过氧化物、氢氧化物和酮衍生物），以及来自丝氨酸极性头和溶血糖基化 PS 氧化裂解的产物。葡萄糖 C6 上的氧化导致葡萄糖醛基-PS 的形成。此外，还鉴定出了源于葡萄糖部分（C1C2、C2C3 和 C3C4 键之间）氧化裂解的新产物，即 PS-AGEs。这些发现大大增加了我们对 PS 糖基化产物的了解，为在复杂生物基质中检测这些产物开辟了新的视角。
