Becher B M, Cassim J Y
Prep Biochem. 1975;5(2):161-78. doi: 10.1080/00327487508061568.
Techniques for purifying teh purple membrane of Halobacterium halobium are given. This purple membrane contains a chromoprotein with a retinal prosthetic group similar to rhodopsin, the chromprotein found in the visual systems of higher invertebrates and vertebrates. The described purple membrane isolation procedures yield a highly purified preparation as determined by transmitting electron microscopy and gel electrophoresis. Critical analysis of the absorption spectra of the purple membrane was also employed to establish criteria of purity for the preparation. The visible absorption spectra of the purified purple membrane preparation in buffer was found to have a maximum at 559 nm which shifted to 567 nm on light exposure. No indication of any spectral perturbation arising from bacterioruberin-containing membrane, the major contaminant in purple membrane preparations, was found. Furthermore, the ratio of protein aromatic amino acid absorbance at 280 nm to chromophore absorbance at 567 nm was found to be 1.5 in light-exposed preparations compared to the previously reported ratio of 2.3.-3 The decrease in the value of this ratio is also indicative of an increase in the purity of the purple membrane preparation.
文中给出了纯化嗜盐菌紫膜的技术。这种紫膜含有一种带有视黄醛辅基的色蛋白，类似于在高等无脊椎动物和脊椎动物视觉系统中发现的视紫红质这种色蛋白。通过透射电子显微镜和凝胶电泳测定，所描述的紫膜分离程序产生了高度纯化的制剂。还对紫膜的吸收光谱进行了严格分析，以确定制剂的纯度标准。发现纯化的紫膜制剂在缓冲液中的可见吸收光谱在559nm处有最大值，光照后移至567nm。未发现来自紫膜制剂中的主要污染物——含细菌红素的膜产生的任何光谱扰动迹象。此外，与之前报道的2.3 - 3的比例相比，光照制剂中蛋白质芳香族氨基酸在280nm处的吸光度与发色团在567nm处的吸光度之比为1.5。该比例值的降低也表明紫膜制剂纯度的提高。
