Irwin C C
J Neurochem. 1985 Feb;44(2):433-8. doi: 10.1111/j.1471-4159.1985.tb05433.x.
Qualitative aspects of protein synthesis in organelles and intact cultured cells of brain origin were compared to clarify the distinction between synaptosomal and mitochondrial protein synthesis. Brain mitochondria and synaptosomes were isolated either on a traditional Ficoll-sucrose gradient or by a new Percoll gradient procedure, and were incubated in an amino acid incorporation system containing [35S]methionine, then electrophoresed on gradient slab gels. Autoradiography of the gels revealed that in the presence of cycloheximide both mitochondria and synaptosomes synthesized at least 17 proteins in the 6,000-50,000 MW range, and that incubation with chloramphenicol reduced or eliminated these bands. With minor variation these patterns in the low-molecular-weight region also resembled patterns obtained from cycloheximide-inhibited rat liver mitochondria and intact brain cells (cultured glia, glioma, and neuroblastoma). In the higher molecular weight region of the gels (greater than 50,000) banding patterns were more complex and tended to differ between organelles and intact cells. These polypeptides probably reflect nonmitochondrial protein synthesis, and their variable response to inhibitors may account for confusion in the literature with regard to the effects of inhibitors of protein synthesis in brain mitochondria and synaptosomes.
为了阐明突触体和线粒体蛋白质合成之间的区别，对源自脑的细胞器和完整培养细胞中蛋白质合成的定性方面进行了比较。脑线粒体和突触体通过传统的Ficoll-蔗糖梯度或新的Percoll梯度程序进行分离，并在含有[35S]甲硫氨酸的氨基酸掺入系统中孵育，然后在梯度平板凝胶上进行电泳。凝胶的放射自显影显示，在环己酰亚胺存在下，线粒体和突触体均合成了至少17种分子量在6,000-50,000范围内的蛋白质，并且用氯霉素孵育可减少或消除这些条带。在低分子量区域，这些模式虽有细微差异，但也类似于从环己酰亚胺抑制的大鼠肝线粒体和完整脑细胞（培养的神经胶质细胞、神经胶质瘤细胞和成神经细胞瘤细胞）获得的模式。在凝胶的较高分子量区域（大于50,000），条带模式更为复杂，并且细胞器和完整细胞之间往往存在差异。这些多肽可能反映了非线粒体蛋白质合成，它们对抑制剂的可变反应可能解释了文献中关于脑线粒体和突触体中蛋白质合成抑制剂作用的混淆。
