Fitt P S, Sharma N, Attia J, Korecky B
Department of Biochemistry, University of Ottawa, Ontario, Canada.
Mol Cell Biochem. 1987 Nov;78(1):37-46. doi: 10.1007/BF00224422.
The acid-insoluble product isolated from well-oxygenated Langendorff rat heart after perfusion with [14C]adenosine was purified by phenol extraction and subjected to specific phosphorolysis by pure polynucleotide phosphorylase. TLC analysis of the reaction mixture showed that ADP was the only radioactive product, proving that the original substance was a polyribonucleotide. Studies of the time course of labelling and of the distribution of the acid-insoluble product between the mitochondrial and nuclear fractions showed that both are labelled even after 1 min at 25 degrees C, but at short times and low temperature more radioactivity is found in the mitochondria. The kinetics of adenosine incorporation resemble those expected for the labelling of hnRNA and mRNA. Isolated, respiring mitochondria incorporate adenosine and adenine nucleotides into acid insoluble form by a process dependent on oxidative phosphorylation and the adenine nucleotide translocase that is specific for adenine derivatives. The results are discussed in terms of the hypothesis that the polyribonucleotide might be a storage form of adenine nucleotides: it is concluded that the bulk of the labelled product is unlikely to play a major role in energy metabolism.
用[14C]腺苷灌注充分氧合的Langendorff大鼠心脏后分离得到的酸不溶性产物，通过苯酚萃取进行纯化，并经纯多核苷酸磷酸化酶进行特异性磷酸解。反应混合物的薄层层析分析表明，ADP是唯一的放射性产物，证明原始物质是一种多聚核糖核苷酸。对标记时间进程以及酸不溶性产物在线粒体和细胞核部分之间分布的研究表明，即使在25℃下孵育1分钟后，两者均被标记，但在短时间和低温条件下，线粒体中的放射性更强。腺苷掺入的动力学与hnRNA和mRNA标记预期的动力学相似。分离的、进行呼吸作用的线粒体通过依赖氧化磷酸化和对腺嘌呤衍生物具有特异性的腺嘌呤核苷酸转位酶的过程，将腺苷和腺嘌呤核苷酸掺入酸不溶性形式。根据多聚核糖核苷酸可能是腺嘌呤核苷酸的一种储存形式这一假说对结果进行了讨论：得出的结论是，大部分标记产物不太可能在能量代谢中起主要作用。
