Castora F J, Lazarus G M, Kunes D
Biochem Biophys Res Commun. 1985 Jul 31;130(2):854-66. doi: 10.1016/0006-291x(85)90495-4.
We have undertaken a study of DNA topoisomerases in mitochondria from human acute leukemia cells. Two activities have been detected in these organelles. One of the enzymes is presumably a type II topoisomerase, i.e., in ATP-dependent reactions it can catenate closed circular plasmid DNA, and decatenate closed circular kinetoplast DNA. A second topoisomerase is presumably a type I enzyme since, it can relax positive as well as negative supercoils in an ATP-independent reaction, it is unable to catenate plasmid DNA or decatenate kinetoplast DNA, and it is inhibited, rather than stimulated, by ATP.
我们对人类急性白血病细胞线粒体中的DNA拓扑异构酶进行了研究。在这些细胞器中检测到了两种活性。其中一种酶可能是II型拓扑异构酶，即在ATP依赖的反应中，它可以使闭合环状质粒DNA形成连环体，并使闭合环状动质体DNA解连环。第二种拓扑异构酶可能是I型酶，因为它可以在不依赖ATP的反应中松弛正超螺旋和负超螺旋，它不能使质粒DNA形成连环体或使动质体DNA解连环，并且它受到ATP的抑制而非刺激。
