Chepurnova N K, Liakhov D L, Rechinskiĭ V O, Karpeĭskiĭ M Ia
Biokhimiia. 1988 Apr;53(4):609-12.
The ability of the strain Bacillus thuringiensis var. subtoxicus to produce extracellular ribonuclease (ribonuclease Bt) was studied. It was found that the culture medium possesses a RNA-depolymerizing activity whose maximum is observed 4-5 hours after the beginning of the linear growth phase. A three-step chromatography of the culture extract on phosphocellulose resulted in a homogeneous enzyme with a molecular mass of 12000 Da. The enzyme showed the maximum activity towards RNA at pH 8.5, catalyzed the hydrolysis of polyribonucleotides and guanosine-2',3'-cyclophosphate. Hence, the enzyme can be related to base-nonspecific cyclizing ribonucleases showing the guanylic specificity towards nucleoside-2',3'-cyclophosphates.
对苏云金芽孢杆菌亚种菌株产生细胞外核糖核酸酶（核糖核酸酶Bt）的能力进行了研究。发现培养基具有RNA解聚活性，其最大值在对数生长期开始后4 - 5小时出现。培养提取物在磷酸纤维素上进行三步层析，得到了一种分子量为12000 Da的纯酶。该酶在pH 8.5时对RNA表现出最大活性，催化多聚核糖核苷酸和鸟苷 - 2',3'-环磷酸酯的水解。因此，该酶可归为对核苷 - 2',3'-环磷酸酯具有鸟苷酸特异性的碱基非特异性环化核糖核酸酶。
