STRUCTURAL & CELL BIOLOGY IN CARDIOVASCULAR DISEASE

来自受刺激的小鼠腹膜巨噬细胞的神经节苷脂 分为单唾液酸和多唾液酸两类，其结构 通过质量检查聚唾液酸部分的实体特征 光谱测定法。 样品被制备为全甲基化衍生物 评估更多的结构细节并提高灵敏度。 NIS 研究之前用唾液酸酶治疗表明 大多数多唾液酸部分具有唾液酸酶抗性 GMla 型 含有少量 asialoGM1 的碱基。 详细的结构分析 通过高碘酸盐氧化和质谱分析表明完全 不存在任何串联二唾液酸部分。 主要神经节苷脂 聚唾液酸部分由 GDla 实体组成，包括 IV3-NeuAc,113NeuAc-GgOse4Cer, IV3-NeuGc,113NeuAc-GgOse4Cer, IV3NeuAc,]II3NeuGc-GgOse4Cer 和 IV3-NeuGc,H3NeuGc-GgOse4Cer。 的 次要成分包括 GDIa 实体、IV3NeuAc、 [1116] 1116NeuAcGgOse4Cer、IV3NeuGc、1116NeuGcGgOse4Cer，和 GDla(NeuAc,NeuGc) 其中位置异构体不能是 确定。 与之前的分析一致，神经酰胺部分 所有聚唾液酸神经节苷脂仅含有 C18 鞘氨醇和 C16 和C24脂肪酸部分。 这些结果表明生物合成 沿着“a”神经节苷脂途径进行（例如，GM3-->GM2->Gma->Gdla） 以及拟议的去唾液酸神经节侧或“oc”途径， asialoGM->GM[lb- GDl(x。p 敏感神经节苷脂似乎是 鼠免疫细胞的特征。

Gangliosides from stimulated murine peritoneal macrophages were separated into monosialo and polysialo factions and the structural character of entities of the polysialo fraction were examined by mass spectrometry. The samples were prepared as permethylated derivatives to evaluate greater structural detaiI and improve sensitivity. Treatment with sialidase prior to NIS studies indicated that the majority of the polysialo fraction had a sialidase-resistant GMla type base with a minor amount of asialoGM1. Detailed structural analyses by periodate oxidation and mass spectrometry indicated a complete absence of any tandem disialo moieties. The major gangliosides in the polysialo fraction consisted of GDla entities comprising IV3-NeuAc,113NeuAc-GgOse4Cer, IV3-NeuGc,113NeuAc-GgOse4Cer, IV3NeuAc,]II3NeuGc-GgOse4Cer, and IV3-NeuGc,H3NeuGc-GgOse4Cer. The minor components consisted of GDIa entities, IV3NeuAc, 1116NeuAcGgOse4Cer, IV3NeuGc, 1116NeuGcGgOse4Cer, and GDla(NeuAc,NeuGc) where the positional isomer(s) could not be determined. Consistent with previous analyses, ceramide portions of all polysialo gangliosides contained solely C18 sphingosine with C16 and C24 fatty acid moieties. These results suggest biosynthesis to proceed along the "a" ganglioside pathway (e.g., GM3-->GM2->Gma->Gdla) and the proposed asialoganglio side or "oc" pathway, asialoGM->GM[lb-+GDl(x. The p sensitive gangliosides appears to be characteristic of murine immune cells.