Aström J, Aström A, Virtanen A
Department of Medical Genetics, Uppsala University, Sweden.
J Biol Chem. 1992 Sep 5;267(25):18154-9.
A HeLa cell 3'-exonuclease with properties of a mammalian mRNA poly(A) tail-removing enzyme has been characterized. The exonuclease shows high specificity for the poly(A) tail, and it is single strand-specific and requires a 3'-hydroxyl group for its activity. During degradation 5'-AMP is liberated as a product, and a 3'-OH group is left on the last adenosine residue of the remaining poly(A) tail. The activity is inhibited by 5'-AMP and can be competed by poly(A)-containing mRNA or poly(A). Based on these findings we propose a reaction pathway for poly(A) tail removal catalyzed by the HeLa cell poly(A) tail-specific 3' exonuclease.
一种具有哺乳动物mRNA聚腺苷酸尾去除酶特性的HeLa细胞3'-外切核酸酶已得到鉴定。该外切核酸酶对聚腺苷酸尾具有高度特异性，它是单链特异性的，并且其活性需要一个3'-羟基。在降解过程中，5'-AMP作为产物被释放出来，并且在剩余聚腺苷酸尾的最后一个腺苷残基上留下一个3'-OH基团。该活性受到5'-AMP的抑制，并且可以被含聚腺苷酸的mRNA或聚腺苷酸竞争。基于这些发现，我们提出了由HeLa细胞聚腺苷酸尾特异性3'外切核酸酶催化的聚腺苷酸尾去除反应途径。
