Baker J R, Caterson B
J Biol Chem. 1979 Apr 10;254(7):2387-93.
A preparation containing the link proteins may be obtained from bovine nasal cartilage by extraction with 4 M guanidine hydrochloride and by equilibrium density gradient centrifugations of the extract as commonly employed in the isolation of proteoglycan monomers. In the present paper, protein-rich proteoglycans have been removed from such a preparation to give purified link proteins by chromatography on Sepharose CL-6B in 1% sodium dodecyl sulfate. The individual link proteins, which in order of increasing electrophoretic mobility are termed link proteins 1, 2, and 3, have been separated and isolated in a subsequent preparative gel electrophoresis step. The link proteins present in largest amount, link proteins 1 and 2, have essentially the same amino acid compositions, and following partial digestion with the V8 protease from Staphylococcus aureus and analytical electrophoresis in sodium dodecyl sulfate, their peptide patterns closely resemble each other. Therefore,it is probable that link proteins 1 and 2 are structurally similar. Link protein 1 contains more carbohydrate than link protein 2 (9.5% and 3.0%, respectively) and it is suggested that the major difference between them is in carbohydrate content.
一种含有连接蛋白的制剂可通过用4M盐酸胍提取牛鼻软骨，并按照常用于分离蛋白聚糖单体的方法对提取物进行平衡密度梯度离心来获得。在本文中，通过在1%十二烷基硫酸钠中于琼脂糖CL-6B上进行层析，已从此类制剂中去除了富含蛋白质的蛋白聚糖，从而得到纯化的连接蛋白。在随后的制备性凝胶电泳步骤中，已分离并纯化了电泳迁移率递增的各个连接蛋白，分别命名为连接蛋白1、2和3。含量最多的连接蛋白1和2，其氨基酸组成基本相同，在用金黄色葡萄球菌的V8蛋白酶进行部分消化并在十二烷基硫酸钠中进行分析电泳后，它们的肽图谱彼此非常相似。因此，连接蛋白1和2在结构上可能相似。连接蛋白1比连接蛋白2含有更多的碳水化合物（分别为9.5%和3.0%），有人认为它们之间的主要区别在于碳水化合物含量。
