Watanabe K, Laine R A, Hakomori S I
Biochemistry. 1975 Jun 17;14(12):2725-33. doi: 10.1021/bi00683a026.
H-Active ceramide heptasaccharide (H2-glycolipid) and ceramide decasaccharide (H3-glycolipid) were isolated from blood group O human erythrocyte membranes. Their structures have been determined by conventional methylation analysis, enzymatic degradation, and direct total mass spectrometry of the enzymatic degradation products after permethylation and reduction with sodium bis(2-methoxyethoxy)aluminum hydride. The branched sugar residue in the structure of H3-glycolipid was unambiguously determined by a new method with the combination of enzymatic degradation and comparison of the total mass spectrogram of the reduced product of the enzyme-degraded compounds. The proposed structures are as follows: (see article) The fourth component of H-active glycolipid (H4-glycolipid) was also isolated in chromatographically heterogenous form, but chemical analysis and methylation study indicate heterogeneity of the fraction. Both H3- and H4-glycolipids inhibit I-hemagglutination, whereas H1- and H2-glycolipids do not inhibit I-hemagglutination.
H-活性神经酰胺七糖（H2-糖脂）和神经酰胺十糖（H3-糖脂）从O型人红细胞膜中分离得到。它们的结构已通过常规甲基化分析、酶促降解以及对经全甲基化和用双（2-甲氧基乙氧基）氢化铝钠还原后的酶促降解产物进行直接全质谱分析来确定。通过酶促降解与酶降解化合物还原产物的总质谱图比较相结合的新方法，明确确定了H3-糖脂结构中的分支糖残基。所提出的结构如下：（见文章）H-活性糖脂的第四种成分（H4-糖脂）也以色谱异质形式分离得到，但化学分析和甲基化研究表明该组分具有异质性。H3-和H4-糖脂均抑制I-血凝，而H1-和H2-糖脂不抑制I-血凝。
