Tarsio J F, Haldar D
Proc Soc Exp Biol Med. 1983 Dec;174(3):415-20. doi: 10.3181/00379727-174-41756.
Possible sites in the mitochondrial protein synthetic/degradative scheme that might be responsible for the increased incorporation of [3H]leucine into protein by mitochondria isolated from regenerating liver over the levels found for mitochondria isolated from sham-operated controls were examined. The rate of degradation of newly synthesized protein in mitochondrial preparations from regenerating liver was not decreased but proceeded approximately 30% greater than that found for the sham-operated controls. The increased incorporation of [3H]leucine into protein could also not be accounted for by a stimulation in the extent of formation of leucyl-tRNALeu. In another experiment, isolated mitochondria were incubated with [3H]leucine and the input of mitochondrial ribosomes from regenerating liver and sham-operated controls equalized for analysis on sucrose density gradients. The 55-S ribosomes from regenerating liver mitochondria contained 2.7-fold greater radioactivity in their nascent polypeptide chains than those from control mitochondria. These results indicate that the stimulation in amino acid incorporation into protein due to liver regeneration is the direct result of enhanced polypeptide bond formation on mitochondrial ribosome-messenger RNA complexes.
研究了线粒体蛋白质合成/降解过程中可能导致从再生肝分离的线粒体比从假手术对照分离的线粒体将[³H]亮氨酸掺入蛋白质的量增加的位点。来自再生肝的线粒体制剂中新合成蛋白质的降解速率并未降低，而是比假手术对照的降解速率高约30%。[³H]亮氨酸掺入蛋白质的增加也不能用亮氨酰-tRNA亮氨酸形成程度的刺激来解释。在另一项实验中，将分离的线粒体与[³H]亮氨酸一起孵育，并使来自再生肝和假手术对照的线粒体核糖体输入量相等，以便在蔗糖密度梯度上进行分析。来自再生肝线粒体的55-S核糖体在其新生多肽链中的放射性比对照线粒体的核糖体高2.7倍。这些结果表明，肝脏再生导致氨基酸掺入蛋白质增加是线粒体核糖体-信使RNA复合物上多肽键形成增强的直接结果。
