Smith E L, McKibbin J M
J Biol Chem. 1975 Aug 10;250(15):6059-64.
A fucolipid that carried human blood group Lea activity was isolated from human small intestine. It contianed fucose, galactose, N-acetyl glucosamine, glucose, and ceramide in a molar ratio of 1:2:1:1:1. After periodate oxidation only 1 molecule of galactose and the N-acetylglucosamine remained. Permethylation of the lipid gave derivatives of a terminal fucose and galactose residue together with 2,4,6-tri-O-methylgalactose and 2,3,6-tri-O-methylglucose. After removal of fucose the lipid could be converted to a ceramide trihexoside with beta-galactosidase, and this, in turn, to ceramide lactoside by the action of beta-N-acetylhexosaminidase. Both enzymes converted the defucosylated derivative to a ceramide monohexoside. The methylated and the methylated and reduced derivatives of the intact lipid gave ions in mass spectrometry for a terminal hexose and deoxyhexose, a terminal trisaccharide of hexose, deoxyhexose and N-acetylhexosamine, and terminal tetra-and pentasaccharides. Ceramide fragments characteristic of hydroxy fatty acids with 16, 22, 23, and 24 carbons were found together with those of phytospingosine as the major long chain base. On the basis of these results and the immunologic activity of the fucolipid, the following structure is proposed: betaGal (1 leads to 3)betaGlcNAc (1 leads to 3)betaGal (1 leads to 4)Glc-ceramide alphaFuc (1 leads to 4).
一种具有人血型Lea活性的岩藻糖脂从人小肠中分离出来。它含有岩藻糖、半乳糖、N-乙酰葡糖胺、葡萄糖和神经酰胺，摩尔比为1:2:1:1:1。高碘酸盐氧化后，仅剩下1分子半乳糖和N-乙酰葡糖胺。该脂质的全甲基化产生了末端岩藻糖和半乳糖残基的衍生物，以及2,4,6-三-O-甲基半乳糖和2,3,6-三-O-甲基葡萄糖。去除岩藻糖后，该脂质可通过β-半乳糖苷酶转化为神经酰胺三己糖苷，进而通过β-N-乙酰己糖胺酶的作用转化为神经酰胺乳糖苷。两种酶都将去岩藻糖基化衍生物转化为神经酰胺单己糖苷。完整脂质的甲基化和甲基化并还原的衍生物在质谱中产生了末端己糖和脱氧己糖、末端由己糖、脱氧己糖和N-乙酰己糖胺组成的三糖，以及末端四糖和五糖的离子。发现了具有16、22、23和24个碳的羟基脂肪酸特征的神经酰胺片段，以及作为主要长链碱基的植物鞘氨醇的片段。基于这些结果和岩藻糖脂的免疫活性，提出了以下结构：βGal(1→3)βGlcNAc(1→3)βGal(1→4)Glc-神经酰胺αFuc(1→4)。
