摘要：The redox chemistry of sanazole, an efficient hypoxic cell radiosensitizer, generally referred to as AK-2123, was studied by pulse radiolysis with e aq - , CO 2 -· , 2-propanol radicals and · CH 2 OH radicals. AK-2123 reacts with e aq - , CO 2 -· and 2-propanol radicals at almost diffusion-controlled rates, producing a nitro radical anion (λ max =290 nm) within a few microseconds. The decay kinetics of the radical anion was independent of the pH. The radical anion reacts with oxygen with a rate constant of 3.4×10 6 dm 3 mol -1 s -1 . An electron-transfer reaction was observed from the thymine radical anion to AK-2123. From redox equilibria with methyl viologen, the one-electron reduction potential of AK-2123 in aqueous solution, determined by pulse radiolysis, was estimated to be -0.33±0.02 V vs. NHE. Depletion of intracellular nonprotein thiols did not mitigate the radiosensitizing affect of the hypoxic radiosensitizer, AK-2123.
关键词：Pulse radiolysis; Electron transfer; Reduction potential; Free radicals; Thiol depletion
