Zdebska E, Musielak M, Jaeken J, Kościelak J
Department of Biochemistry, Institute of Hematology and Blood Transfusion, ul. Chocimska 5, 00-957 Warsaw, Poland.
Proteomics. 2001 Feb;1(2):269-74. doi: 10.1002/1615-9861(200102)1:2<269::AID-PROT269>3.0.CO;2-8.
Band 3 and PAS-1 (a dimer of glycophorin A) from erythrocyte membranes of three children with congenital disorder of glycosylation, type Ia (CDG-Ia), aged 1 month, 3 years and 10 years respectively, were examined by a new technique that allowed determination of carbohydrate molar composition of glycoproteins separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis. In CDG children a single N-glycan of band 3 glycoprotein was hypoglycosylated and its mannose content was normal or elevated. Glycophorin A which is the major carrier of erythrocyte sialic acid, was deficient in N-acetylgalactosamine, and sialic acid residues. This finding indicated a partial unglycosylation of O-glycans in glycophorin A. In keeping with the results of PAS-1 analysis, total sialic acid in erythrocyte membranes from CDG children was reduced to 40-56% of normal values. A possible molecular mechanism of hypo- and unglycosylation of band 3 and glycophorin A, respectively, in CDG is discussed.
分别对三名患有糖基化先天性疾病Ia型（CDG-Ia）的儿童（年龄分别为1个月、3岁和10岁）红细胞膜上的带3蛋白和PAS-1（血型糖蛋白A的二聚体）进行了检测，采用了一种新技术，该技术能够测定通过十二烷基硫酸钠聚丙烯酰胺凝胶电泳分离的糖蛋白的碳水化合物摩尔组成。在患有CDG的儿童中，带3糖蛋白的单个N-聚糖糖基化不足，其甘露糖含量正常或升高。作为红细胞唾液酸主要载体的血型糖蛋白A，N-乙酰半乳糖胺和唾液酸残基缺乏。这一发现表明血型糖蛋白A中的O-聚糖存在部分去糖基化。与PAS-1分析结果一致，患有CDG的儿童红细胞膜中的总唾液酸减少至正常值的40%-56%。本文讨论了CDG中带3蛋白和血型糖蛋白A分别发生低糖基化和去糖基化的可能分子机制。
