Bronk B V, Van de Merwe W P
Mutat Res. 1983 Apr;112(2):109-18. doi: 10.1016/0167-8817(83)90015-9.
The curves of UV (254 nm) induced pyrimidine dimers (endonuclease sensitive sites) vs. photoreactivating blacklight (365 nm) dose for cultured chick embryo fibroblasts reveal several new features. When the cells are incubated in the dark at 37 degrees following UV (254 nm) treatment, the efficiency of subsequent photorepair increases for the first few hours post-UV. The efficiency then remains approximately constant for several hours. Photorepair data obtained during this later period were plotted as the logarithm of dimer-enzyme complexes available for photoreactivation vs. blacklight (365 nm) dose. For a fixed damaging UV (254 nm) dose, the resulting curve has a shoulder of approximately 6-10 kJ/m2 followed by a straight line portion with a slope of magnitude about 1.5 X 10(-4) m2/J for UV doses up to 15 J/m2. For higher UV doses the shoulder remains about the same, but the slope decreases in magnitude. The shoulder is interpreted to indicate that a light-dependent step is necessary to activate the enzyme. The decrease in slope with increased UV dose together with some split photoreactivation dose experiments suggests that some site-to-site motion and multiple site function of the photorepair enzyme molecules may come into play at the higher levels of damage, but the evidence indicates that these complications are relatively unimportant at low UV doses.
紫外线（254纳米）诱导的嘧啶二聚体（核酸内切酶敏感位点）与培养的鸡胚成纤维细胞的光复活黑光（365纳米）剂量曲线显示出几个新特征。在用紫外线（254纳米）处理后，将细胞在37摄氏度黑暗中孵育，紫外线照射后的最初几个小时内，后续光修复的效率会提高。然后该效率会在几个小时内大致保持恒定。将在此后期获得的光修复数据绘制成可用于光复活的二聚体 - 酶复合物的对数与黑光（365纳米）剂量的关系图。对于固定的损伤紫外线（254纳米）剂量，所得曲线有一个约6 - 10千焦/平方米的肩部，随后是一个直线部分，对于高达15焦耳/平方米的紫外线剂量，其斜率大小约为1.5×10⁻⁴平方米/焦耳。对于更高的紫外线剂量，肩部大致保持不变，但斜率大小会减小。肩部被解释为表明激活该酶需要一个光依赖步骤。随着紫外线剂量增加斜率减小以及一些光复活剂量分割实验表明，在更高水平的损伤时，光修复酶分子的一些位点到位点的移动和多位点功能可能会起作用，但证据表明这些复杂情况在低紫外线剂量时相对不重要。
