Azuma J, Kashimura N, Komano T
J Biochem. 1975 Jun;77(6):1185-92.
The low-density lipoproteins in pig serum were separated into two subclasses (LDL1 and LDL2) by 2 to 7% pore size gradient gel electrophoresis. Preparative gel electrophoresis in 2 to 4% gradient gel made it possible to isolate these components as distinct entities. After delipidation by chromatography on Sepharose 4B in the presence of SDS, both apo-LDL1 and apo-LDL2 were found to have a molecular weight of 2.6X10(5). However, when these apoproteins were incubated in 10% sodium dodecyl sulfate, fragmentation occurred and the minimum fragment molecular weight was estimated to be 2.4X10(4). No essential difference was found in the amino acid compositions or fragmentation patterns of the apoproteins. However, the amounts of carbohydrates in the two apoproteins were different (7.09% in apo-LDL1 and 5.08% in apo-LDL2). The carbohydrate composition was 0.8% sialic acid, 2.38% N-acetyl-glucosamine, and 4.01% neutral sugars in apo-LDL1 and 0.5, 1.75, and 2.83% in apo-LDL2, respectively. In both apoproteins, mannose, galactose, and fucose were present in almost the same molar ratio of 4-5 : 2-3 : 1.
通过孔径为2%至7%的梯度凝胶电泳，猪血清中的低密度脂蛋白被分离为两个亚类（LDL1和LDL2）。在2%至4%的梯度凝胶中进行制备性凝胶电泳，使得这些成分能够作为不同的实体被分离出来。在SDS存在的情况下，通过Sepharose 4B柱层析进行脱脂后，发现载脂蛋白LDL1和载脂蛋白LDL2的分子量均为2.6×10⁵ 。然而，当这些载脂蛋白在10%的十二烷基硫酸钠中孵育时，会发生片段化，估计最小片段分子量为2.4×10⁴ 。在载脂蛋白的氨基酸组成或片段化模式上未发现本质差异。然而，两种载脂蛋白中的碳水化合物含量不同（载脂蛋白LDL1中为7.09%，载脂蛋白LDL2中为5.08%）。载脂蛋白LDL1中的碳水化合物组成分别为0.8%的唾液酸、2.38%的N - 乙酰葡糖胺和4.01%的中性糖，载脂蛋白LDL2中的分别为0.5%、1.75%和2.83%。在两种载脂蛋白中，甘露糖、半乳糖和岩藻糖的摩尔比几乎相同，为4 - 5 : 2 - 3 : 1。
