摘要
本文用改进的方法从一些动物组织中抽提了DNA拓扑异构酶Ⅱ,并用电镜、电泳方法对该酶解结活性进行了鉴定。酶活力测定结果表明该酶在不同组织中分布不尽相同,增殖较旺盛的组织具有相对较高的酶活性。pH值、温度、一些激动剂、抑制剂及组织的状态均对酶活力有影响。
The enzyme extracts were prepared from purified nuclei of mammalian cells and concentrated by fractionational precipitation of ammonium sulfate. The ATP dependent unknotting activity of topoisomerase Ⅱ in extracts was assayed by monitoring the conversion of P4 knotted DNA to relaxed circular DNA. This conversion was detected quantitatively by electrophoresis and confirmed by electron microscopy. The optimum reaction conditions were also defined. Thus, quantitation of the unknotting activity of topoisomerase Ⅱ was possible under the present procedure and defined conditions. Our results showed that there were different specific activities in different tissues but not in different species. The higher unknotting activity seemed to be associated with cell proliferation.
基金
国家自然科学基金3860324号资助
关键词
DNA拓扑异构酶
DNA解结反应
细胞
动物
组织
DNA topoisomerase Ⅱ, DNA unknotting reaction, P4 knotted DNA, Cell proliferation
