Beale E G, Katzen C S, Granner D K
Biochemistry. 1981 Aug 18;20(17):4878-83. doi: 10.1021/bi00520a012.
N6,O2'-Dibutyryladenosine 3',5'-phosphate (Bt2cAMP) induces the synthesis of the gluconeogenic enzyme, phosphoenolpyruvate carboxykinase (GTP) (EC 4.1.32), in rat liver by increasing the activity of messenger ribonucleic acid (mRNA) coding for this enzyme (mRNAPEPCK) more than 20-fold (from less than 0.01% to greater than 0.20% of total mRNA activity) as determined by using in vitro translation systems which measure only active mRNAPEPCK. The increase in mRNAPEPCK activity could result from increased synthesis, increased processing, or decreased inactivation rates. Actinomycin D and cordycepin inhibit mRNAPEPCK induction by 89% and 70%, respectively, a result that indicates a requirement for ongoing RNA synthesis but that does not distinguish which of these steps is regulated by cAMP. We have employed a kinetic approach, not involving RNA synthesis inhibitors, to determine the half-life of mRNAPEPCK both during a period of deinduction following glucose feeding and during a subsequent induction by Bt2cAMP. An estimated half-life of 20 +/-5 min during both of these periods indicates that Bt2cAMP has no effect on the rate of inactivation of mRNAPEPCK. We conclude that Bt2cAMP effects the increase in activity of mRNAPEPCK by promoting its synthesis or processing.
N6,O2'-二丁酰腺苷3',5'-磷酸（Bt2cAMP）通过使编码磷酸烯醇丙酮酸羧激酶（GTP）（EC 4.1.32）的信使核糖核酸（mRNA）的活性增加20多倍（从占总mRNA活性的不到0.01%增加到大于0.20%），从而诱导大鼠肝脏中糖异生酶磷酸烯醇丙酮酸羧激酶（GTP）的合成，这一活性增加是通过使用仅测量活性mRNA（mRNAPEPCK）的体外翻译系统测定的。mRNAPEPCK活性的增加可能是由于合成增加、加工增加或失活速率降低所致。放线菌素D和虫草素分别抑制mRNAPEPCK的诱导89%和70%，这一结果表明需要持续的RNA合成，但无法区分这些步骤中哪一个受cAMP调节。我们采用了一种不涉及RNA合成抑制剂的动力学方法，来测定在葡萄糖喂养后的去诱导期以及随后Bt2cAMP诱导期内mRNAPEPCK的半衰期。在这两个时期估计的半衰期均为20±5分钟，这表明Bt2cAMP对mRNAPEPCK的失活速率没有影响。我们得出结论，Bt2cAMP通过促进mRNAPEPCK的合成或加工来影响其活性的增加。
