Basnakyan A G, Antoni F, Bubnov N V, Votrin I I, Bánfalvi G
Institute of Medical Enzymology, Academy of Medical Science, Moscow, USSR.
Acta Biochim Biophys Hung. 1987;22(4):409-24.
The distribution of different types of DNase in rat liver nuclei was determined after a purification procedure involving ion exchange chromatography and gel filtration. As major enzymes Ca2+, Mg2+-dependent endonuclease, Mn2+-dependent endonuclease and an acid endonuclease were identified, sharing 60, 20 and 10% of the total activity, respectively. Mn2+-dependent endonuclease is a novel enzyme with a molecular mass of 30 +/- 5 kilodaltons. The synergistic effect of Ca2+ and Mg2+ ions for the Mn2+-dependent enzyme was lower by an order of magnitude than that of the Ca2+ and Mg2+-dependent endonuclease. The Ca2+ and Mg2+-dependent nuclease activity represents a heterogeneous population of enzymes. One of the cation dependent enzymes (Mr 25 +/- 5 kD) is stimulated by ATP the ATP optimum being 0.1 mM and the Mg2+ requirement 1 mM. The ATP-dependent endonuclease belongs to the minor endonucleases separable from the major ones.
经过离子交换色谱和凝胶过滤的纯化程序后，测定了大鼠肝细胞核中不同类型脱氧核糖核酸酶（DNase）的分布。鉴定出作为主要酶的钙离子、镁离子依赖性核酸内切酶、锰离子依赖性核酸内切酶和一种酸性核酸内切酶，它们分别占总活性的60%、20%和10%。锰离子依赖性核酸内切酶是一种新型酶，分子量为30±5千道尔顿。钙离子和镁离子对锰离子依赖性酶的协同作用比钙离子和镁离子依赖性核酸内切酶低一个数量级。钙离子和镁离子依赖性核酸酶活性代表了多种不同的酶。其中一种阳离子依赖性酶（分子量25±5千道尔顿）受ATP刺激，ATP的最适浓度为0.1 mM，镁离子需求量为1 mM。ATP依赖性核酸内切酶属于可与主要核酸内切酶分离的次要核酸内切酶。
