Scher B
J Bacteriol. 1976 Apr;126(1):429-38. doi: 10.1128/jb.126.1.429-438.1976.
An endonuclease stimulated by manganese or calcium ions was isolated from Bacillus subtilis. This enzyme attacked double- or single-stranded deoxyribonucleic acid from a variety of sources, including B. subtilis, and was purified from the material released into the medium during protoplast formation. The enzyme appeared as a single peak after glycerol gradient centrifugation and comprised approximately 30 to 35% of the protein in the most purified preparations, as estimated by gel electrophoresis. It had a molecular weight of about 46,000. The mode of action of the enzyme was endonucleolytic, and circular deoxyribonucleic acid was readily cleaved. The enzyme introduced a limited number of both double- and single-strand breaks into native deoxyribonucleic acid, generally yielding products of 1 X 10(6) daltons or more in size. The reasons for this limitation of cleavage were not clear. The activity of the enzyme was inhibited by low levels of Cu2+, Co2+, Hg2+, and Zn2+. It was also inhibited by high concentrations of NaCl. A role for this enzyme in bacterial transormation is suggested.
从枯草芽孢杆菌中分离出一种受锰离子或钙离子刺激的核酸内切酶。这种酶能作用于来自多种来源（包括枯草芽孢杆菌）的双链或单链脱氧核糖核酸，并且是从原生质体形成过程中释放到培养基中的物质中纯化得到的。经甘油梯度离心后，该酶呈现为单一峰，根据凝胶电泳估计，在最纯的制剂中其蛋白质含量约占30%至35%。它的分子量约为46,000。该酶的作用方式是核酸内切，环状脱氧核糖核酸很容易被切割。该酶在天然脱氧核糖核酸中引入有限数量的双链和单链断裂，通常产生大小为1×10⁶道尔顿或更大的产物。这种切割限制的原因尚不清楚。该酶的活性受到低水平的Cu²⁺、Co²⁺、Hg²⁺和Zn²⁺的抑制。它也受到高浓度NaCl的抑制。有人提出这种酶在细菌转化中起作用。
