Vinayak M
Biochem Int. 1986 Mar;12(3):479-84.
Total tRNA extracted from livers of young (7 +/- 1 weeks), adult (40 +/- 1 weeks) and old (80 +/- 1 weeks) rats showed quantitative variation with age, being maximal in adults. Young and old animals yielded almost the same level of tRNAs. Quantitative changes in tRNAs were also observed from the study of amino acid acceptor activity using homologous enzyme i.e., aminoacyl-tRNA synthetase preparations from rat liver of the same age group. Quantitative variation followed the trend of qualitative variation. When tRNA was amino-acylated with a heterologous enzyme system, i.e., synthetase preparation from rat liver of another age group, age-related variation in aminoacyl-tRNA did not follow a pattern similar to that in the case of the homologous enzyme system. Young and adult synthetase enzymes showed maximum affinity for their homologous tRNAs but synthetases from old rat liver did not show any specific affinity for "old" tRNAs. This shows that apart from tRNAs, enzyme activity also changes with age.
从幼年（7±1周）、成年（40±1周）和老年（80±1周）大鼠肝脏中提取的总tRNA显示出随年龄的定量变化，在成年大鼠中含量最高。幼年和老年动物产生的tRNA水平几乎相同。通过使用同源酶（即来自同一年龄组大鼠肝脏的氨酰-tRNA合成酶制剂）研究氨基酸接受活性，也观察到了tRNA的定量变化。定量变化遵循定性变化的趋势。当tRNA用异源酶系统进行氨酰化时，即来自另一年龄组大鼠肝脏的合成酶制剂，氨酰-tRNA的年龄相关变化并不遵循与同源酶系统类似的模式。幼年和成年合成酶对其同源tRNA表现出最大亲和力，但老年大鼠肝脏中的合成酶对“老年”tRNA没有表现出任何特异性亲和力。这表明除了tRNA外，酶活性也随年龄变化。
