Herrler G, Geyer R, Müller H P, Stirm S, Klenk H D
Virus Res. 1985 Mar;2(2):183-92. doi: 10.1016/0168-1702(85)90248-5.
Purified alpha 1-macroglobulin (RMG) isolated from rat plasma was found to be a potent inhibitor of hemagglutination by influenza C virus. Neuraminidase treatment of purified RMG reduced its inhibitory activity by more than 80% indicating that sialic acid is required for maximal HI-activity. The inhibitory activity of RMG was shown to be sensitive to the receptor-destroying activity (RDA) of influenza C virus. Methylation analysis of the glycopeptides of RMG indicated the presence of only one major type of oligosaccharide which is a complex N-linked oligosaccharide with a biantennary structure. Comparison of the glycopeptides before and after neuraminidase treatment revealed that the oligosaccharides are terminated by sialic acid residues attached to galactose residues at position C-6. Methylation analysis was also performed on RMG which had lost its inhibitory activity upon incubation with RDA of influenza C virus. No difference between the glycopeptides of native and inactive RMG could be detected. Galactose was found to be substituted at position C-6 in both samples, indicating that also the oligosaccharides of inactive RMG are terminated by sialic acid. The implications of these results are discussed.
从大鼠血浆中分离出的纯化α1-巨球蛋白（RMG）被发现是丙型流感病毒血凝作用的有效抑制剂。用神经氨酸酶处理纯化的RMG后，其抑制活性降低了80%以上，这表明唾液酸是最大血凝抑制（HI）活性所必需的。RMG的抑制活性对丙型流感病毒的受体破坏活性（RDA）敏感。对RMG糖肽的甲基化分析表明，仅存在一种主要类型的寡糖，即具有双天线结构的复杂N-连接寡糖。神经氨酸酶处理前后糖肽的比较显示，寡糖由连接在C-6位半乳糖残基上的唾液酸残基终止。对与丙型流感病毒RDA孵育后失去抑制活性的RMG也进行了甲基化分析。未检测到天然RMG和失活RMG糖肽之间的差异。在两个样品中均发现半乳糖在C-6位被取代，这表明失活RMG的寡糖也由唾液酸终止。讨论了这些结果的意义。
