Hildenbrand K, Schulte-Frohlinde D
Max-Planck-Institut für Strahlenchemie, Mülheim a.d. Ruhr, Germany.
Int J Radiat Biol. 1997 Apr;71(4):377-85. doi: 10.1080/095530097143996.
Electron paramagnetic resonance (EPR) signals of peroxyl radicals of poly(acrylic acid), PAA, and of single- and double-stranded DNA were generated at 293 K and pH 6.6 by in situ photolysis of O2-saturated aqueous solutions containing the macromolecules and H2O2. From time-resolved EPR measurements upper limits for the rate constants of reaction of glutathione (GSH) with the peroxyl radicals of PAA [kb < or = (0.8 +/- 0.2) x 10(2) dm3 mol-1S-1] and of single- and double-stranded DNA from calf thymus [kb < or = (2 +/- 2) x 10(2) dm3 mol-1S-1] were determined. The low value of kb for reaction of GSH with DNA peroxyl radicals is in agreement with the observed lack of protective effect of the thiol in radiation-induced DNA strand break reactions (Liphard et al. 1990).
通过对含有大分子和过氧化氢的氧气饱和水溶液进行原位光解，在293K和pH 6.6条件下产生了聚丙烯酸（PAA）以及单链和双链DNA的过氧自由基的电子顺磁共振（EPR）信号。通过时间分辨EPR测量，确定了谷胱甘肽（GSH）与PAA过氧自由基反应速率常数的上限[kb ≤ (0.8 ± 0.2) × 10² dm³ mol⁻¹ s⁻¹]以及小牛胸腺单链和双链DNA的反应速率常数上限[kb ≤ (2 ± 2) × 10² dm³ mol⁻¹ s⁻¹]。GSH与DNA过氧自由基反应的kb值较低，这与在辐射诱导的DNA链断裂反应中观察到的硫醇缺乏保护作用一致（Liphard等人，1990年）。
