Nishizawa M, Tanabe K, Takahashi T
Biochem Biophys Res Commun. 1984 Nov 14;124(3):917-24. doi: 10.1016/0006-291x(84)91045-3.
DNA topoisomerase activity together with the activities of DNA polymerase were detected in a form tightly associated with rat liver nuclear matrices. DNA polymerase activities were solubilized from the nuclear matrices of regenerating rat livers by sonic treatment followed by extraction of these activities with detergent and salt. The predominant activity was mainly alpha-polymerase as judged from the size determined by sucrose density gradient centrifugation. However, only beta-polymerase activity was detected in the matrix of normal rat livers. DNA topoisomerase activity, detected in both regenerating and normal liver nuclear matrices, showed a molecular size of about 4 S in sucrose gradient, and was active in the presence of EDTA. These results suggest that this enzyme belongs to type I topoisomerase.
在与大鼠肝细胞核基质紧密相关的形式中检测到了DNA拓扑异构酶活性以及DNA聚合酶的活性。通过超声处理从再生大鼠肝脏的核基质中溶解DNA聚合酶活性，随后用去污剂和盐提取这些活性。从蔗糖密度梯度离心确定的大小判断，主要活性主要是α-聚合酶。然而，在正常大鼠肝脏的基质中仅检测到β-聚合酶活性。在再生和正常肝细胞核基质中均检测到的DNA拓扑异构酶活性，在蔗糖梯度中的分子大小约为4S，并且在EDTA存在下具有活性。这些结果表明该酶属于I型拓扑异构酶。
