Feit H, Slusarek L, Shelanski M L
Proc Natl Acad Sci U S A. 1971 Sep;68(9):2028-31. doi: 10.1073/pnas.68.9.2028.
Tubulin, the subunit protein of microtubules, is a dimer that sediments at 6 S and has a molecular weight of 110,000. Using high resolution polyacrylamide gel electrophoresis, we have demonstrated the presence of two peptide chains, of molecular weight 56,000 and 53,000, in tubulin purified from brain. Two peptide chains of similar molecular weight were identified in each of the A- and B-tubulins isolated from flagella of sea urchin sperm. In all cases, the protein concentrations in the bands were equal. Each of the subunits ran as a single band when eluted from the gel and electrophoresed again in the same type of gel. Chromatography of purified brain tubulin on DEAE-Sephadex columns gave only a single peak containing both subunits in equal amounts. Cyanogen bromide peptides were prepared from each of the bands after elution from polyacrylamide gel. While certain of the peptides appear to be common to both subunits, substantial differences exist between them. The tubulin dimer is composed of two nonidentical subunits.
微管蛋白是微管的亚基蛋白，是一种沉降系数为6S、分子量为110,000的二聚体。利用高分辨率聚丙烯酰胺凝胶电泳，我们已经证明从脑中纯化的微管蛋白中存在分子量分别为56,000和53,000的两条肽链。在从海胆精子鞭毛中分离出的A-微管蛋白和B-微管蛋白中均鉴定出两条分子量相似的肽链。在所有情况下，条带中的蛋白质浓度相等。当从凝胶中洗脱并在同类型凝胶中再次电泳时，每个亚基都以单一条带形式迁移。纯化的脑微管蛋白在DEAE-葡聚糖凝胶柱上进行层析，只得到一个包含等量两个亚基的单一峰。从聚丙烯酰胺凝胶上洗脱后，从每个条带制备了溴化氰肽。虽然某些肽似乎是两个亚基共有的，但它们之间存在显著差异。微管蛋白二聚体由两个不同的亚基组成。
