PHOSPHORYLATION OF DNA TOPOISOMERASE-II BY CASEIN KINASE-II - MODULATION OF EUKARYOTIC TOPOISOMERASE-II ACTIVITY INVITRO
PHOSPHORYLATION OF DNA TOPOISOMERASE-II BY CASEIN KINASE-II - MODULATION OF EUKARYOTIC TOPOISOMERASE-II ACTIVITY INVITRO
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DOI：
10.1073/pnas.82.10.3164
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发表时间：
1985-01-01
影响因子：
11.1
通讯作者：
OSHEROFF, N
中科院分区：
文献类型：
--
作者：
ACKERMAN, P;GLOVER, CVC;OSHEROFF, N
纯化的酪蛋白激酶 II 对果蝇 DNA 拓扑异构酶 II 的磷酸化进行了体外表征。在所使用的条件下，激酶掺入最多 2-3 个拓扑异构酶 II 磷酸盐/同型二聚体分子。没有观察到拓扑异构酶的自磷酸化。酪蛋白激酶 II 修饰的唯一氨基酸残基是丝氨酸。磷酸化反应的表观Km和Vmax值分别为0.4μM拓扑异构酶II和3.3μmol磷酸盐掺入/分钟/mg激酶。磷酸化对拓扑异构酶 II 的 DNA 松弛活性的刺激是去磷酸化酶的 3 倍，并且修饰的效果可以通过用碱性磷酸酶处理来逆转。翻译后酶促修饰可用于调节拓扑异构酶 II 和 DNA 之间的相互作用。
The phosphorylation of Drosophila melanogaster DNA topoisomerase II by purified casein kinase II was characterized in vitro. Under the conditions used, the kinase incorporated a maximum of 2-3 molecules of phosphate/homodimer of topoisomerase II. No autophosphorylation of the topoisomerase was observed. The only amino acid residue modified by casein kinase II was serine. Apparent Km and Vmax values for the phosphorylation reaction were 0.4 .mu.M topoisomerase II and 3.3 .mu.mol of phosphate incorporated/min per mg of kinase, respectively. Phosphorylation sitmulated the DNA relaxation activity of topoisomerase II by 3-fold over that of the dephosphorylated enzyme, and the effects of modification could be reversed by treatment with alkaline phosphatase. Posttranslational enzymatic modifications can be used to modulate the interaction between topoisomerase II and DNA.