Nagai Ryoji, Hayashi Cristina Miki, Xia Ling, Takeya Motohiro, Horiuchi Seikoh
Department of Biochemistry and Second Department of Pathology, Kumamoto University School of Medicine, Japan.
J Biol Chem. 2002 Dec 13;277(50):48905-12. doi: 10.1074/jbc.M205688200. Epub 2002 Oct 10.
Glycolaldehyde (GA) is formed from serine by action of myeloperoxidase and reacts with proteins to form several products. Prominent among them is N(epsilon)-(carboxymethyl)lysine (CML), which is also known as one of the advanced glycation end products. Because CML is formed from a wide range of precursors, we have attempted to identify unique structures characteristic of the reaction of GA with protein. To this end, monoclonal (GA5 and 1A12) and polyclonal (non-CML-GA) antibodies specific for GA-modified proteins were prepared. These antibodies specifically reacted with GA-modified and with hypochlorous acid-modified BSA, but not with BSA modified by other aldehydes, indicating that the epitope of these antibodies could be a specific marker for myeloperoxidase-induced protein modification. By HPLC purification from GA-modified N(alpha)-(carbobenzyloxy)-l-lysine, GA5-reactive compound was isolated, and its chemical structure was characterized as 3-hydroxy-4-hydroxymethyl-1-(5-amino-5-carboxypentyl) pyridinium cation. This compound named as GA-pyridine was recognized both by 1A12 and non-CML-GA, indicating that GA-pyridine is an important antigenic structure in GA-modified proteins. Immunohistochemical studies with GA5 demonstrated the accumulation of GA-pyridine in the cytoplasm of foam cells and extracellularly in the central region of atheroma in human atherosclerotic lesions. These results suggest that myeloperoxidase-mediated protein modification via GA may contribute to atherogenesis.
乙醇醛（GA）由髓过氧化物酶作用于丝氨酸形成，并与蛋白质反应形成多种产物。其中突出的是N（ε）-（羧甲基）赖氨酸（CML），它也被认为是晚期糖基化终产物之一。由于CML由多种前体形成，我们试图鉴定GA与蛋白质反应特有的独特结构。为此，制备了对GA修饰蛋白具有特异性的单克隆抗体（GA5和1A12）和多克隆抗体（非CML-GA）。这些抗体与GA修饰的和次氯酸修饰的牛血清白蛋白（BSA）特异性反应，但不与其他醛修饰的BSA反应，这表明这些抗体的表位可能是髓过氧化物酶诱导的蛋白质修饰的特异性标志物。通过从GA修饰的N（α）-（苄氧羰基）-L-赖氨酸进行高效液相色谱纯化，分离出GA5反应性化合物，其化学结构被鉴定为3-羟基-4-羟甲基-1-（5-氨基-5-羧基戊基）吡啶阳离子。这种化合物被命名为GA-吡啶，可被1A12和非CML-GA识别，表明GA-吡啶是GA修饰蛋白中的重要抗原结构。用GA5进行的免疫组织化学研究表明，GA-吡啶在人动脉粥样硬化病变的泡沫细胞胞质中以及动脉粥样硬化中央区域的细胞外积聚。这些结果表明，髓过氧化物酶通过GA介导的蛋白质修饰可能促成动脉粥样硬化的发生。
