动物组织及细胞DNA拓扑异构酶Ⅱ提取及解结活性的比较研究  

A Comparative Study of the Unknotting Activity of Mammalian DNA Topoisomerase Ⅱ

作　　者：钱毅[1] 曾桂超[1] 张迺蘅[1] 程乃乾 

机构地区：[1]北京医科大学生化教研室 [2]北京大学生物系电镜室

出　　处：《生物化学杂志》1990年第2期123-128,共6页

基　　金：国家自然科学基金3860324号资助

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.

关 键 词：DNA拓扑异构酶 DNA解结反应 细胞 动物 组织 

分 类 号：Q555.03[生物学—生物化学]