Chigorno V, Sonnino S, Ghidoni R, Tettamanti G
Department of Biological Chemistry, The Medical School, University of Milan, Milan, Italy.
Neurochem Int. 1982;4(6):531-9. doi: 10.1016/0197-0186(82)90042-0.
A new ganglioside, containing an alkali-labile linkage, was extracted from mouse brain and purified. It represents 3.6% of total lipid-bound sialic acid in the tissue and was obtained in pure form with a yield of about 35%. It contains sphingosine, glucose, galactose, N-acetylgalactosamine and sialic acid in the molar ratio 1:1:2:1:4 and, upon exhaustive sialidase treatment gives the monosialoganglioside GM1. Partial acid hydrolysis, methylation analysis, gas-liquid chromatography-mass spectrometry and chromium trioxide oxidation studies showed its basic neutral glycosphingolipid core to be ganglio-N-tetraose-ceramide. Three of the four sialic acid residues are N-acetylneuraminic acid and one, as shown by gas-liquid chromatography-mass spectrometry, is 9-O-acetyl,N-acetylneuraminic acid, which contains the alkali labile linkage. 9-O-acetyl,N-acetylneuraminic acid is ?-ketosidically linked to position 8 of the N-acetylneuraminic acid residue bound to position 3 of the internal galactose. The other two N-acetylneuraminic acid residues form a disialosyl residue linked to position 3 of external galactose. The complete structure of the studied ganglioside is as follows: NeuAc?2-8NeuAc?2-3Gal?1-3GalNAc?1-4(9-O-Ac-NeuAca?2-8NeuAc?2-1?-N-acylsphingosine, and it can be considered as a derivative of the tetrasialoganglioside GQ1b.
从鼠脑中提取并纯化出一种含有碱不稳定键的新神经节苷脂。它占该组织中总脂质结合唾液酸的3.6%，并以纯形式获得，产率约为35%。它含有鞘氨醇、葡萄糖、半乳糖、N-乙酰半乳糖胺和唾液酸，摩尔比为1:1:2:1:4，经彻底的唾液酸酶处理后得到单唾液酸神经节苷脂GM1。部分酸水解、甲基化分析、气-液色谱-质谱联用以及三氧化铬氧化研究表明，其基本的中性糖鞘脂核心是神经节-N-四糖神经酰胺。四个唾液酸残基中的三个是N-乙酰神经氨酸，如气-液色谱-质谱联用所示，另一个是9-O-乙酰基-N-乙酰神经氨酸，它含有碱不稳定键。9-O-乙酰基-N-乙酰神经氨酸以α-酮糖苷键连接到与内部半乳糖3位相连的N-乙酰神经氨酸残基的8位。另外两个N-乙酰神经氨酸残基形成一个二唾液酸残基，连接到外部半乳糖的3位。所研究的神经节苷脂完整结构如下：NeuAcα2-8NeuAcα2-3Galβ1-3GalNAcβ1-4(9-O-Ac-NeuAcaα2-8NeuAcα2-1)-N-酰基鞘氨醇，它可被视为四唾液酸神经节苷脂GQ1b的衍生物。
