Pérez J L, Dorta B, González-Cadavid N
Mol Cell Biochem. 1984 Jun;62(2):121-32. doi: 10.1007/BF00223302.
Purified mitochondria from rat liver were found to contain protein synthesis inhibitors, that could be extracted by disruption of mitochondrial membranes and fractionated by gel filtration into two fractions of low and high molecular weight. Small size inhibitors were also released from the latter peak by high ionic strength followed by gel filtration. Both types of factors inhibit incorporation of radioactive amino acids into protein by liver cytoplasmic polysomes programmed with endogenous mRNA or poly U, and by rabbit reticulocyte lysates programmed with added globin mRNA and by incubations of Walker carcinoma cells. They decrease to the same level the cytoplasmic synthesis of proteins for the mitochondrial and extra-mitochondrial compartments in intact cells, but do not appear to inhibit substantially endogenous mitochondrial protein synthesis. Inhibitors were purified by paper chromatography and reverse phase high performance liquid chromatography into fractions which block with the same kinetics the incorporation of [14]leucine and [35]methionine into protein in systems able to initiate protein synthesis, such as reticulocyte lysates or intact cells, but differ in this respect in incubations of liver ribosomes where re-binding of mRNA is a limiting step. Some of these factors behave as oligopeptides that are assumed to inhibit in vitro primarily the initiation stage but whose function in vivo is still undetermined.
研究发现，从大鼠肝脏中分离得到的纯化线粒体含有蛋白质合成抑制剂，这些抑制剂可通过破坏线粒体膜进行提取，并通过凝胶过滤分离为低分子量和高分子量两个组分。高离子强度处理后再经凝胶过滤，小分子抑制剂也可从后一个峰中释放出来。这两种类型的因子均可抑制放射性氨基酸掺入由内源性mRNA或聚尿苷酸编程的肝脏细胞质多核糖体、由添加的珠蛋白mRNA编程的兔网织红细胞裂解物以及沃克癌细胞培养物中的蛋白质中。它们使完整细胞中线粒体和线粒体外部分的细胞质蛋白质合成降至相同水平，但似乎并未显著抑制内源性线粒体蛋白质合成。通过纸层析和反相高效液相色谱法将抑制剂纯化成分，这些成分在能够起始蛋白质合成的系统（如网织红细胞裂解物或完整细胞）中，以相同的动力学阻断[14]亮氨酸和[35]甲硫氨酸掺入蛋白质，但在肝脏核糖体培养物中，mRNA的重新结合是一个限制步骤，在这方面存在差异。其中一些因子表现为寡肽，推测其在体外主要抑制起始阶段，但其在体内的功能仍未确定。
