Pulleyblank D E, Ellison M J
Biochemistry. 1982 Mar 16;21(6):1155-61. doi: 10.1021/bi00535a008.
A simple method for the purification of the major topoisomerase (topoisomerase 1) from chicken erythrocytes is described. Because of the generally repressed state of the chromatin from these nuclei, the heterogeneity of the non-histone proteins is reduced, and it is possible to purify this enzyme from a nuclear extract by a single chromatographic step. The chicken erythrocyte topoisomerase appears to be similar to previously described eukaryotic type I topoisomerases with respect to its physical and enzymological properties. The pattern of intermediate products generated during the action of chicken erythrocyte topoisomerase on a supercoiled closed circular DNA substrate has been examined quantitatively and has been shown to be consistent with a mechanism in which the enzyme closes its substrate DNA molecular after the removal of each superhelical turn and in which dissociation of the enzyme substrate complex may, but does not necessarily, occur after each cycle of the reaction.
本文描述了一种从鸡红细胞中纯化主要拓扑异构酶（拓扑异构酶1）的简单方法。由于这些细胞核中染色质通常处于抑制状态，非组蛋白的异质性降低，因此可以通过单一色谱步骤从核提取物中纯化这种酶。鸡红细胞拓扑异构酶在物理和酶学性质方面似乎与先前描述的真核I型拓扑异构酶相似。对鸡红细胞拓扑异构酶作用于超螺旋闭环DNA底物过程中产生的中间产物模式进行了定量研究，结果表明该机制与以下情况一致：酶在去除每一圈超螺旋后封闭其底物DNA分子，并且酶-底物复合物的解离可能（但不一定）在每个反应循环后发生。
