Tóth K, Csik G, Rontó G Y
Physiol Chem Phys Med NMR. 1987;19(1):67-74.
Optically detected thermal stability and biological activity of phage T7 has been compared as the function of the ionic composition and strength of the buffers. The ionic strength range was studied between 20-140 mmol/1. In Tris buffer containing only monovalent ions the biological activity of the phages decreases abruptly below 50 mmol/1 ionic strength. Structural studies show a logarithmic dependence between the ionic strength and the intraphage DNA stability and no significant change in the thermal stability of the whole phage. Mg2+ and Ca2+ ions at low concentration (1 mmol/1) given into a Tris buffer of 20 mmol/1 original ionic strength highly stabilize the biological activity, which stabilization is also to be seen in the intraphage DNA and also in the whole phage thermal denaturation process.
已将噬菌体T7的光学检测热稳定性和生物活性作为缓冲液离子组成和强度的函数进行了比较。研究的离子强度范围在20-140 mmol/1之间。在仅含单价离子的Tris缓冲液中，噬菌体的生物活性在离子强度低于50 mmol/1时会突然下降。结构研究表明，离子强度与噬菌体内部DNA稳定性之间存在对数依赖性，而整个噬菌体的热稳定性没有显著变化。将低浓度（1 mmol/1）的Mg2+和Ca2+离子加入到原始离子强度为20 mmol/1的Tris缓冲液中，可高度稳定生物活性，这种稳定性在噬菌体内部DNA以及整个噬菌体热变性过程中也能观察到。
