Akrigg A
Biochem J. 1978 Apr 15;172(1):69-76. doi: 10.1042/bj1720069.
A DNAase (deoxyribonuclease) was isolated from culture supernatants of sporulating Bacillus subtilis 168. The purified enzyme migrated as a single band during polyacrylamide-gel electrophoresis. The enzyme differs from other DNAases of B. subtilis in molecular weight, metal-ion requirement and mode of action. The enzyme was inactive in the absence of metal ions, and exhibited optimum activity with 10 mM-Mn2+, although Mg2+, Cd2+ and Co2+ could also permit some activity. The pH optimum for the enzyme was pH 7.5, and it degraded linear-duplex DNA or closed-circular-duplex DNA to acid-soluble material. There was little or no activity on single-stranded DNA or rRNA. Sucrose-gradient analysis of the products of DNAase action on bacteriophage T7 DNA showed that endonucleolytic cleavage had occurred by the introduction of single-strand breaks in both strands of the duplex. The molecular weight of the enzyme was determined, by gel filtration on Sephadex G-75, to be 12000.
从枯草芽孢杆菌168芽孢形成期的培养上清液中分离出一种脱氧核糖核酸酶（DNAase）。纯化后的酶在聚丙烯酰胺凝胶电泳中呈单一泳带。该酶在分子量、金属离子需求和作用方式上与枯草芽孢杆菌的其他DNAase不同。该酶在没有金属离子的情况下无活性，在10 mM - Mn2+存在时表现出最佳活性，不过Mg2+、Cd2+和Co2+也能使其具有一定活性。该酶的最适pH为7.5，它能将线性双链DNA或闭环双链DNA降解为酸溶性物质。对单链DNA或rRNA几乎没有活性。对噬菌体T7 DNA进行DNAase作用产物的蔗糖梯度分析表明，双链的两条链均通过引入单链断裂发生了内切核酸酶切割。通过在Sephadex G - 75上进行凝胶过滤测定，该酶的分子量为12000。
