Lee C C, Timms K M, Trotman C N, Tate W P
J Biol Chem. 1987 Mar 15;262(8):3548-52.
A single release factor has been isolated and partially purified from rat mitochondria. It requires ethanol in addition to the specific termination codon when assayed in a heterologous system with Escherichia coli ribosomes. The factor recognizes the codons UAA and UAG but not UGA, and therefore it has been designated mtRF-1. A factor of the bacterial RF-2 type, which in E. coli recognizes UGA, or of the mammalian type, which recognizes all three termination codons, has not been detected in mitochondria. The absence of a factor responding to UGA accommodates the use of this codon as a signal for tryptophan in the rat mitochondrial genetic code. The mtRF-1 could translate all of the known termination codons in the rat mitochondrial genome. It does not respond to AGG and AGA which in bovine and human mitochondrial DNA code for termination but which in rat mitochondria may not code for either an amino acid or for termination.
已从大鼠线粒体中分离并部分纯化出一种单一的释放因子。在用大肠杆菌核糖体的异源系统中进行检测时，除了特定的终止密码子外，它还需要乙醇。该因子识别密码子UAA和UAG，但不识别UGA，因此被命名为mtRF-1。在大鼠线粒体中未检测到细菌RF-2类型（在大肠杆菌中识别UGA）或哺乳动物类型（识别所有三个终止密码子）的因子。不存在对UGA有反应的因子，这与大鼠线粒体遗传密码中使用该密码子作为色氨酸信号的情况相符。mtRF-1可以翻译大鼠线粒体基因组中所有已知的终止密码子。它对AGG和AGA无反应，在牛和人的线粒体DNA中，AGG和AGA编码终止，但在大鼠线粒体中可能既不编码氨基酸也不编码终止。
