Identification of disialic acid-containing glycoproteins in mouse serum: a novel modification of immunoglobulin light chains, vitronectin, and plasminogen.
Identification of disialic acid-containing glycoproteins in mouse serum: a novel modification of immunoglobulin light chains, vitronectin, and plasminogen.
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DOI：
10.1093/glycob/cwj112
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发表时间：
2006-07
期刊：
影响因子：
4.3
通讯作者：
Zenta Yasukawa;C. Sato;Kotone Sano;H. Ogawa;K. Kitajima
中科院分区：
文献类型：
--
作者：
Zenta Yasukawa;C. Sato;Kotone Sano;H. Ogawa;K. Kitajima
血清糖蛋白参与多种生物活性，例如去除外源性抗原、纤维蛋白溶解和金属转运。其中一些也是炎症和疾病的有用标志物。虽然炎症后唾液酸的量增加，但很少注意血清中存在的连接特异性表位，特别是α 2，8-连接。在先前的研究中，基于与单克隆抗体2- 4 B的免疫反应性，我们证明小鼠血清中的四种组分含有α 2，8-连接的二唾液酸（diSia），其对N-羟乙酰神经氨酸（Neu 5Gc）α 2->（8 Neu 5Gc α 2->）（n-1）具有特异性，n >或= 2 [Yasukawa et al.，（2005）Glycobiology，15，827-837]。在这项研究中，我们纯化的三个组件，30-，70-，和120-kDa的糖蛋白，并确定它们作为免疫球蛋白（IG）轻链，玻连蛋白，纤溶酶原，分别使用基质辅助激光解吸/电离飞行时间质谱分析。通过荧光C7/C9分析和温和的酸水解产物-荧光阴离子交换色谱分析，化学确认了这些蛋白质与α 2，8-连接的diSia的修饰。我们还证明了IgG、IgM和IgE轻链通常用α 2，8-连接的diSia修饰。此外，小鼠和大鼠玻连蛋白均含有二唾液酸化，肝切除术后玻连蛋白中的二唾液酸化量显著降低。这些结果表明，血清糖蛋白的新型diSia修饰对于免疫事件和纤维蛋白溶解具有生物学重要性。
Serum glycoproteins are involved in various biologic activities, such as the removal of exogenous antigens, fibrinolysis, and metal transport. Some of them are also useful markers of inflammation and disease. Although the amount of sialic acid increases following inflammation, little attention has been paid to the presence of linkage-specific epitopes in serum, especially the alpha2,8-linkage. In a previous study, we demonstrated that four components in mouse serum contain alpha2,8-linked disialic acid (diSia), based on immunoreactivity with monoclonal antibody 2-4B, which is specific to N-glycolylneuraminic acid (Neu5Gc)alpha2-->(8Neu5Gc alpha2-->)(n-1), n > or = 2 [Yasukawa et al., (2005) Glycobiology, 15, 827-837]. In this study, we purified three components, 30-, 70-, and 120-kDa gp, and identified them as an immunoglobulin (Ig) light chain, vitronectin, and plasminogen, respectively, using matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy analyses. Modifications of these proteins with alpha2,8-linked diSia were chemically confirmed by fluorometric C7/C9 analyses and mild acid hydrolysates-fluorometric anion-exchange chromatography analyses. We also demonstrated that the IgG, IgM, and IgE light chains are commonly modified with alpha2,8-linked diSia. In addition, both mouse and rat vitronectin contained diSia, and the amount of disialylation in vitronectin dramatically decreased after hepatectomy. These results indicate that a novel diSia modification of serum glycoproteins is biologically important for immunologic events and fibrinolysis.