Bubnov N V, Basnak'ian A G, Votrin I I
Biokhimiia. 1986 Jul;51(7):1194-202.
The endogenous endonuclease activity of chromatin in isolated rat liver nuclei in the presence of Mn2+, Mg2+ and Ca2+ + Mg2+ was studied. The existence of a Mn2+-dependent endonuclease activity not coupled with the Ca2+, Mg2+-dependent endonuclease was demonstrated, which was weaker than the former one in isolated cell nuclei but higher than in the preparation of Ca2+, Mg2+-dependent nuclease obtained by gel filtration through Toyopearl HW 60F. The Mn2+-dependent splitting of chromatin predominantly occurs at linker DNA of distal parts of chromatin loops. A split-off of purified DNA was more universal than in the presence of Ca2+, Mg2+-dependent endonuclease; the hydrolysis rate of native and denaturated DNA appeared to be the same.
研究了在存在锰离子（Mn2+）、镁离子（Mg2+）以及钙离子（Ca2+）与镁离子（Mg2+）的情况下，分离的大鼠肝细胞核中染色质的内源性核酸内切酶活性。证实了存在一种不依赖于钙离子（Ca2+）、镁离子（Mg2+）的依赖锰离子（Mn2+）的核酸内切酶活性，其在分离的细胞核中比前者弱，但比通过Toyopearl HW 60F凝胶过滤获得的依赖钙离子（Ca2+）、镁离子（Mg2+）的核酸酶制剂中的活性高。染色质依赖锰离子（Mn2+）的裂解主要发生在染色质环远端部分的连接DNA处。纯化DNA的裂解比存在依赖钙离子（Ca2+）、镁离子（Mg2+）的核酸内切酶时更普遍；天然和变性DNA的水解速率似乎相同。
