CHARACTER OF SCHIFF BASE FORMED IN REACTION OF P HYDROXYLPHENYLACETALDEHYDE

醛类修饰蛋白质时形成的加合物已经被 与血管疾病和衰老的发病机制有关。 我们 以前的研究表明，对羟基苯乙醛（pHA）， 髓过氧化物酶氧化L-酪氨酸的主要产物-氢 过氧化物-氯化物系统的吞噬细胞，共价修饰 炎症部位赖氨酸残基的（-氨基）。 这里我们 报道，pHA也与合成的氨基反应， 磷脂和红细胞模型系统。 快原子轰击 乙醇胺甘油磷脂的质谱分析 检测到与pHA和NaCNBH 3孵育的丝氨酸甘油磷脂 共价加合物与还原磷脂Schiff 碱加合物 我们证实了醛与 氨基通过1H NMR和质谱分析的极性 头基从修饰和还原的母体脂质中恢复。 当我们将磷脂模型系统 和细胞膜的生理水平的L-酪氨酸和 髓过氧化物酶-过氧化氢-氯化物系统， 用NaCNBH_3处理，得到pHA的还原席夫碱加合物 用乙醇胺甘油磷脂和丝氨酸甘油磷脂 （分别为pHA-PE和pHA-PS）。 所需的反应 髓过氧化物酶、过氧化氢、L-酪氨酸和氯离子; 被过氧化氢酶或血红素毒素抑制，暗示过氧化物酶在 道路。 总的来说，这些结果表明，醛 产生的髓过氧化物酶系统的吞噬细胞可以共价 修饰乙醇胺甘油磷脂和丝氨酸的氨基 甘油磷脂 因为氨基甘油磷脂 细胞膜的组分和循环脂蛋白如LDL， 类似的反应可能在引发或 炎症部位的疾病进展。

The adducts that form when aldehydes modify proteins have been implicated in the pathogenesis of vascular disease and aging. Our previous studies indicated that p-hydroxyphenylacetaldehyde (pHA), the major product of L-tyrosine oxidation by the myeloperoxidase-hydrogen peroxide-chloride system of phagocytes, covalently modifies the (-amino group of lysine residues at sites of inflammation. Here, we report that pHA also reacts with the amino group of synthetic phospholipids and red blood cell model systems. Fast atom bombardment mass spectrometric analysis of ethanolamine glycerophospholipid or serine glycerophospholipid incubated with pHA and NaCNBH3 detected covalent adducts that were consistent with reduced phospholipid Schiff base adducts. We confirmed the reaction of the aldehyde with the amino group through 1H NMR and mass spectrometric analysis of polar head groups recovered from the modified and reduced parent lipid. When we exposed phospholipid model systems and cell membranes to physiological levels of L-tyrosine and the myeloperoxidase-hydrogen peroxide-chloride system followed by treatment with NaCNBH3, we obtained reduced Schiff base adducts of pHA with ethanolamine glycerophospholipid and serine glycerophospholipid (pHA-PE and pHA-PS, respectively). The reaction required myeloperoxidase, hydrogen peroxide, L-tyrosine and chloride ion; it was inhibited by catalase or heme poisons, implicating a peroxidase in the pathway. Collectively, these results demonstrate that an aldehyde generated by the myeloperoxidase system of phagocytes can covalently modify the amino groups of ethanolamine glycerophospholipid and serine glycerophospholipid. Because amino glycerophospholipids are critical components of cell membranes and circulating lipoproteins such as LDL, similar reactions may play important roles in the initiation or progression of disease at sites of inflammation.