Iusupova D V, Sokolova R B, Gedze G I
Vopr Med Khim. 1983 Mar-Apr;29(2):29-35.
DNAase was isolated and purified from cell-free extracts of Proteus mirabilis by means of fractionation with ammonium sulfate and CM cellulose chromatography. The enzyme exhibited the endonuclease specificity with DNA as a substrate, split off the native DNA by the "single-strike" mechanism, had a pH optimum in alkaline zone, required Me2+ and was inhibited by tRNA. The highest specific activity and the specific rate of the enzyme synthesis were found at lag phase, before the exponential phase of the cell population growth. Microorganisms of Proteus and Salmonella genera had the highest enzymatic activity in cell-free extracts as compared with other enterobacteria. Possible biological functions of the enzyme are discussed.
通过硫酸铵分级分离和CM纤维素色谱法从奇异变形杆菌的无细胞提取物中分离并纯化了DNA酶。该酶以DNA为底物表现出核酸内切酶特异性，通过“单次打击”机制切割天然DNA，在碱性区域具有最适pH值，需要二价金属离子（Me2+）且受tRNA抑制。在细胞群体生长的指数期之前的延迟期发现该酶的比活性和合成比速率最高。与其他肠道杆菌相比，变形杆菌属和沙门氏菌属的微生物在无细胞提取物中的酶活性最高。文中讨论了该酶可能的生物学功能。
