Routledge M N, Wink D A, Keefer L K, Dipple A
Chemistry of Carcinogenesis Laboratory, ABL-Basic Research Program, NCI-FCRDC, Maryland 21702.
Chem Res Toxicol. 1994 Sep-Oct;7(5):628-32. doi: 10.1021/tx00041a007.
To refine our understanding of the mutational spectra one might expect on exposure of human cells to nitric oxide (NO), we have treated the plasmid pSP189 at pH 7.4 with two compounds that generate NO spontaneously in solution, and then sequenced the mutations found when the treated plasmid was transfected into human Ad293 cells and allowed to replicate. G.C-->A.T transitions were the most abundant mutation observed with these NO donor drugs, whereas in previous work, A.T-->G.C transitions predominated when nitric oxide gas was bubbled through the plasmid solution under otherwise identical conditions. A difference in reactive intermediates formed in solution- versus gas-phase NO exposure was demonstrated by treating buffered 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) or ferrocyanide, in the presence or absence of azide, aerobically with preformed solutions of NO, with solutions of the two NO-releasing compounds, or with gaseous mixtures of equimolar NO/O2 in air; oxidation of these substrates was extensive with the gas-phase NO source whether azide was present or not, while azide almost completely quenched the oxidation pathway in the solution-phase reactions.
为了深化我们对人类细胞暴露于一氧化氮（NO）时可能出现的突变谱的理解，我们用两种在溶液中自发产生NO的化合物在pH 7.4条件下处理了质粒pSP189，然后对处理后的质粒转染到人类Ad293细胞中并进行复制后发现的突变进行测序。在这些NO供体药物处理中观察到的最常见突变是G.C→A.T转换，而在之前的工作中，在其他条件相同的情况下，当一氧化氮气体鼓泡通过质粒溶液时，A.T→G.C转换占主导。通过在有或没有叠氮化物存在的情况下，用预先形成的NO溶液、两种释放NO的化合物溶液或空气中等摩尔NO/O₂的气体混合物对缓冲的2,2'-偶氮二（3-乙基苯并噻唑啉-6-磺酸盐）（ABTS）或亚铁氰化物进行好氧处理，证明了在溶液相和气相NO暴露中形成的反应中间体存在差异；无论是否存在叠氮化物，这些底物的氧化在气相NO源作用下都很广泛，而叠氮化物几乎完全抑制了溶液相反应中的氧化途径。
