纯化的聚腺苷酸聚合酶将聚腺苷酸水解为腺嘌呤核苷酸。
Hydrolysis of poly (A) to adenine nucleotides by purified poly (A) polymerase.
作者信息
Abraham A K, Jacob S T
出版信息
Proc Natl Acad Sci U S A. 1978 May;75(5):2085-7. doi: 10.1073/pnas.75.5.2085.
Highly purified poly(A) polymerase (polynucleotide adenylyltransferase, EC 2.7.7.19), which synthesizes poly(A) from ATP substrate, can also catalyze hydrolysis of poly(A). The enzyme, designated as poly(A) hydrolase, requires either Mn2+ or Mg2+ for activity. Although AMP is the predominant product of the reaction, ADP and ATP are also formed. The enzyme is a 3'-exonuclease that does not degrade poly(A) associated with poly(A) poly(U) helical structure. AMP, ADP, and ATP inhibit the hydrolytic reaction. These data suggest that (i) the levels of adenine nucleotides regulate synthesis and degradation of poly(A), (ii) poly(A) itself is a storage form of adenine nucleotides, (iii) the hydrolytic reaction is responsible for poly(A) shortening or turnover observed in vivo, and (iv) the synthetic and hydrolytic activities are functions of the same protein molecule.
高度纯化的聚腺苷酸聚合酶（多核苷酸腺苷酸转移酶，EC 2.7.7.19）可利用ATP底物合成聚腺苷酸（poly(A)），同时也能催化poly(A)的水解。这种被称为聚腺苷酸水解酶的酶，其活性需要Mn2+或Mg2+。尽管AMP是该反应的主要产物，但也会生成ADP和ATP。该酶是一种3'-外切核酸酶，不会降解与聚腺苷酸-聚尿苷酸（poly(A) poly(U)）螺旋结构相关的poly(A)。AMP、ADP和ATP会抑制水解反应。这些数据表明：（i）腺嘌呤核苷酸的水平调节着poly(A)的合成和降解；（ii）poly(A)本身是腺嘌呤核苷酸的一种储存形式；（iii）水解反应导致了体内观察到的poly(A)缩短或周转；（iv）合成和水解活性是同一蛋白质分子的功能。
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