Inouye M, Yee M L
J Bacteriol. 1972 Oct;112(1):585-92. doi: 10.1128/jb.112.1.585-592.1972.
When the envelope fraction of Escherichia coli was treated by trypsin, about 40% of total envelope proteins were removed from the fraction without changing its phospholipid content. Analysis of envelope proteins by acrylamide gel electrophoresis in 0.5% sodium dodecyl sulfate revealed that trypsin treatment was very specific; one of the major proteins (molecular weight, 38,000) and all proteins of molecular weight greater than 70,000 were completely removed by the treatment. On the other hand, three other major proteins were found to be resistant to the treatment, including protein Y, which was previously shown to be related to deoxyribonucleic acid replication. The trypsin treatment of the envelope fractions composed of a five electron-dense layered structure formed vesicles with a triple-layered membrane (two electron-dense layers). Pronase treatment of the envelope fraction removed about 60% of the envelope proteins without changing its phospholipid content. A major protein of molecular weight of 58,000 was found to be the only protein resistant to the Pronase treatment. Application of these treatments is useful for purification and structural studies of envelope proteins.
当用胰蛋白酶处理大肠杆菌的包膜组分时，约40%的包膜总蛋白从该组分中被去除，而其磷脂含量未发生变化。在0.5%十二烷基硫酸钠中通过丙烯酰胺凝胶电泳分析包膜蛋白发现，胰蛋白酶处理具有高度特异性；一种主要蛋白（分子量38,000）以及所有分子量大于70,000的蛋白都被该处理完全去除。另一方面，发现另外三种主要蛋白对该处理具有抗性，包括先前显示与脱氧核糖核酸复制相关的蛋白Y。由具有五层电子致密层结构组成的包膜组分经胰蛋白酶处理后形成了具有三层膜（两层电子致密层）的囊泡。用链霉蛋白酶处理包膜组分可去除约60%的包膜蛋白，而其磷脂含量不变。发现一种分子量为58,000的主要蛋白是唯一对链霉蛋白酶处理具有抗性的蛋白。这些处理方法对于包膜蛋白的纯化和结构研究很有用。
