Piette J, Calberg-Bacq C M, Van de Vorst A
Radiat Environ Biophys. 1979 Apr 30;16(2):125-34. doi: 10.1007/BF01323220.
Induction of peroxide free radicals (detected by Electron Paramagnetic Resonance at 77 K) due to the photodynamic activity of proflavine was measured on bacteriophage phi X174 DNA either single-stranded (ss) as isolated from the virion, or double-stranded supercoiled (RFI) as isolated from the infected bacteria. Comparison was made with calf thymus DNA photosensitization. In order to use equivalent DNA-proflavine complexes, binding of the dye to the three DNA's was first determined under those conditions of high ionic strength favourable to the photodynamic reaction. Free radical induction was maximal for definite amounts of bound proflavine (which varied depending upon the DNA substrate) and at an ionic strength value of 0.5. The level of the maximal reaction increased in the following order: from phi Xss DNA to calf thymus DNA and finally to phi XRFI DNA. The conformation of the proflavine-DNA complex was thus a determinant for the efficiency of the photodynamic process. The ionic strength effect could not be explained by the evolution of the proflavine triplet state in irradiated proflavine-calf thymus DNA complexes.
利用电子顺磁共振在77K下检测，测定了原黄素的光动力活性诱导噬菌体φX174 DNA产生过氧化物自由基的情况，该DNA既可以是从病毒粒子中分离得到的单链（ss）形式，也可以是从受感染细菌中分离得到的双链超螺旋（RFI）形式。并与小牛胸腺DNA的光致敏作用进行了比较。为了使用等效的DNA-原黄素复合物，首先在有利于光动力反应的高离子强度条件下测定了染料与这三种DNA的结合情况。对于一定量结合的原黄素（其含量因DNA底物而异），在离子强度值为0.5时，自由基诱导作用最大。最大反应水平按以下顺序增加：从φXss DNA到小牛胸腺DNA，最后到φXRFI DNA。因此，原黄素-DNA复合物的构象是光动力过程效率的一个决定因素。离子强度效应无法通过照射的原黄素-小牛胸腺DNA复合物中原黄素三重态的演化来解释。
