Irie F, Kurono S, Li Y T, Seyama Y, Hirabayashi Y
Laboratory for Cellular GlycoBiology, Institute of Physical and Chemical Research (RIKEN), Hirosawa, Wako-shi, Saitama, Japan.
Glycoconj J. 1996 Apr;13(2):177-86. doi: 10.1007/BF00731492.
In the present study, three extremely minor but novel Chol-1 antigens, termed X1, X2, and X3 have been isolated from bovine brain gangliosides. Based on the results of sialidase degradation, TLC-immunostaining with anti-Chol-1 antibody and fast atom bombardment mass spectrometry, their chemical structures were identified as: III6NeuAc-GgOse4Cer (X1: GM1 alpha) III6NeuAc,II3NeuAc-GgOse4Cer (X2: GD1a alpha) III6NeuAc,II3NeuAc-NeuGc-GgOse4Cer (X3: GT1b alpha) The yields of GM1 alpha, GD1a alpha, and GT1b alpha, were approximately 150, 20, and 10 micrograms, respectively, from 10 g of the bovine brain ganglioside mixture. In conjunction with our previous observations, all gangliosides with anti-Chol-1 reactivity were found to contain a common sialyl alpha 2-6 N-acetylgalactosamine residue, indicating that this unique sialyl linkage is the specific antigenic determinant. We subsequently examined the biosynthesis of the three novel Chol-1 gangliosides using rat liver Golgi fraction as an enzyme source. The results showed that GM1 alpha, GD1a alpha, and GT1b alpha were synthesized from asialo-GM1, GM1a, and GD1b, respectively, by the action of a GalNAc alpha 2-6sialyltransferase.
在本研究中，从牛脑神经节苷脂中分离出了三种极其微量但全新的Chol-1抗原，分别命名为X1、X2和X3。基于唾液酸酶降解结果、用抗Chol-1抗体进行的薄层层析免疫染色以及快原子轰击质谱分析，确定了它们的化学结构分别为：III6NeuAc-GgOse4Cer（X1：GM1α）、III6NeuAc，II3NeuAc-GgOse4Cer（X2：GD1aα）、III6NeuAc，II3NeuAc-NeuGc-GgOse4Cer（X3：GT1bα）。从10克牛脑神经节苷脂混合物中获得的GM1α、GD1aα和GT1bα的产量分别约为150微克、20微克和10微克。结合我们之前的观察结果，发现所有具有抗Chol-1反应性的神经节苷脂都含有一个共同的唾液酸α2-6 N-乙酰半乳糖胺残基，这表明这种独特的唾液酸连接是特异性抗原决定簇。随后，我们以大鼠肝脏高尔基体部分作为酶源，研究了这三种新型Chol-1神经节苷脂的生物合成。结果表明，GM1α、GD1aα和GT1bα分别由去唾液酸GM1、GM1a和GD1b通过GalNAcα2-6唾液酸转移酶的作用合成。
