DeGasperi R, Koerner T A, Quarles R H, Ilyas A A, Ishikawa Y, Li S C, Li Y T
Department of Biochemistry, Tulane University School of Medicine, New Orleans, Louisiana 70112.
J Biol Chem. 1987 Dec 15;262(35):17149-55.
We have previously reported the presence of GM2 as the major ganglioside in the roe of striped mullet, Mugil cephalus, (Li, Y.-T., Hirabayashi, Y., DeGasperi, R., Yu, R. K., Ariga, T., Koerner, T. A. W., and Li, S.-C. (1984) J. Biol. Chem. 259, 8980-8985). In addition to GM2, mullet roe also contain a series of gangliosides with thin-layer chromatographic mobilities slower than GM2. Besides enzymatic hydrolysis and NMR spectroscopy, we have employed the thin-layer chromatography overlay technique using a human monoclonal IgM antibody which recognizes the GM2 epitope to study the nature of these gangliosides. Using these methods we have isolated and characterized three novel mullet roe gangliosides with the following structures: (Formula: see text). These three gangliosides all contain neolacto-series sugar chains. However, the unique feature of gangliosides 5 and 10 is that the terminal portion of the sugar chain is of the ganglio-series while the internal portion is of the neolacto series structure. Due to the substitution of a GalNAc on the internal Gal in 9 and 10 in the inner core, these two gangliosides also contain the gangliotriaosyl structure. Thus, the sugar chains in these gangliosides are of novel type and can be considered a hybrid between the two series which can be defined as the neolacto-ganglio series.
我们之前曾报道过，条纹鲻鱼（Mugil cephalus）的鱼籽中存在GM2作为主要神经节苷脂（Li, Y.-T., Hirabayashi, Y., DeGasperi, R., Yu, R. K., Ariga, T., Koerner, T. A. W., and Li, S.-C. (1984) J. Biol. Chem. 259, 8980 - 8985）。除了GM2之外，鲻鱼鱼籽还含有一系列在薄层色谱中迁移率比GM2慢的神经节苷脂。除了酶促水解和核磁共振光谱法外，我们还采用了使用识别GM2表位的人单克隆IgM抗体的薄层色谱覆盖技术来研究这些神经节苷脂的性质。使用这些方法，我们分离并鉴定了三种具有以下结构的新型鲻鱼鱼籽神经节苷脂：（分子式：见正文）。这三种神经节苷脂都含有新乳糖系列糖链。然而，神经节苷脂5和10的独特之处在于，糖链的末端部分是神经节系列，而内部部分是新乳糖系列结构。由于在内核中9和10的内部半乳糖上取代了一个N-乙酰半乳糖胺，这两种神经节苷脂还含有神经节三糖基结构。因此，这些神经节苷脂中的糖链是新型的，可以被认为是这两个系列之间的杂合体，可定义为新乳糖 - 神经节系列。
