Fukuda M N, Papayannopoulou T, Gordon-Smith E C, Rochant H, Testa U
Br J Haematol. 1984 Jan;56(1):55-68. doi: 10.1111/j.1365-2141.1984.tb01271.x.
Congenital dyserythropoietic anaemia type II (HEMPAS) is a hereditary disease believed to be caused by a membrane abnormality of erythroid cells. Since the molecular basis of this membrane abnormality has not yet been defined, membrane glycoproteins of HEMPAS erythrocytes were analysed by cell surface labelling and endo-beta-galactosidase digestion in this study. HEMPAS erythrocytes showed an abnormal glycoprotein profile when cells were labelled by the galactose oxidase/NaB[3H]4 method; Band 3 and Band 4.5 glycoproteins in HEMPAS are labelled but with less intensity although normally these proteins are the major components revealed by the same method. Instead, in HEMPAS, labelled lactosaminoglycans were found as a lower molecular weight glycoconjugate (HEMPAS glycan). HEMPAS glycan was characterized by micelle formation, a monomer molecular weight of 4000, susceptibility to endo-beta-galactosidase and resistance to protease. These characteristics suggest that HEMPAS glycan has the nature of macroglycolipid. Proteins of Band 3 and the glucose transport protein (a component of Band 4.5), which were detected by antibodies showed a slightly decreased molecular weight in HEMPAS erythrocytes compared to those from normal erythrocytes, which was consistent with the decreased glycosylation of these proteins. The results indicate that anomalies in glycosylation occurred specifically in lactosaminoglycan glycoproteins of HEMPAS erythrocytes.
II型先天性红细胞生成异常性贫血（HEMPAS）是一种遗传性疾病，被认为是由红系细胞的膜异常引起的。由于这种膜异常的分子基础尚未明确，本研究通过细胞表面标记和内切β-半乳糖苷酶消化对HEMPAS红细胞的膜糖蛋白进行了分析。当用半乳糖氧化酶/NaB[3H]4方法标记细胞时，HEMPAS红细胞显示出异常的糖蛋白谱；HEMPAS中的带3和带4.5糖蛋白被标记，但强度较低，尽管通常这些蛋白是用相同方法显示的主要成分。相反，在HEMPAS中，发现标记的乳糖胺聚糖是一种较低分子量的糖缀合物（HEMPAS聚糖）。HEMPAS聚糖的特征是形成胶束，单体分子量为4000，对内切β-半乳糖苷酶敏感，对蛋白酶有抗性。这些特征表明HEMPAS聚糖具有大糖脂的性质。通过抗体检测到的带3蛋白和葡萄糖转运蛋白（带4.5的一个成分）在HEMPAS红细胞中的分子量与正常红细胞相比略有降低，这与这些蛋白糖基化的减少一致。结果表明，糖基化异常特异性地发生在HEMPAS红细胞的乳糖胺聚糖糖蛋白中。
