Shi X, Dalal N, Kasprzak K S
Laboratory of Comparative Carcinogenesis, National Cancer Institute, Frederick, Maryland.
Environ Health Perspect. 1994 Sep;102 Suppl 3(Suppl 3):91-6. doi: 10.1289/ehp.94102s391.
Electron spin resonance (ESR) spin trapping was utilized to investigate the generation of free radicals from oxidation of sodium sulfite, nickel(II) sulfite, and nickel subsulfide (Ni3S2) by ambient oxygen or H2O2 at pH 7.4. The spin trap used was 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). Under ambient oxygen, a solution of sodium sulfite alone generated predominantly sulfur trioxide anion radical (.SO3-) due to the autoxidation of sulfite. Addition of nickel(II) chloride [Ni(II)] enhanced the .SO3- yield about 4-fold. Incubation of sulfite with Ni(II) in the presence of chelators such as tetraglycine, histidine, beta-alanyl-3-methyl-L-histidine (anserine), beta--L-histidine (carnosine), gamma-aminobutyryl-L-histidine (homocarnosine), glutathione, and penicillamine did not have any significant effect on that enhancement. In contrast, albumin, and especially glycylglycylhistidine (GlyGlyHis), augmented the enhancing effect of Ni(II) by factors of 1.4 and 4, respectively. Computer simulation analysis of the spin-adduct spectrum and formate scavenging experiment showed that the mixture of sodium sulfite, Ni(II), and GlyGlyHis generated both hydroxyl (.OH) radical and .SO3- radical, in the ratio of approximately 1:2. The free-radical spin adduct intensity reached its saturation level in about 5 min. The yield of the radical adducts could be slightly reduced by deferoxamine and very strongly reduced by diethylenetriaminepentaacetic acid (DTPA). Aqueous suspensions of sparingly soluble nickel(II) sulfite in the presence of air and GlyGlyHis generated surface-located .SO3- and .OH radicals. The same radicals were generated in Ni3S2 suspension in the presence of GlyGlyHis and H2O2, indicating sulfite production by oxidation of the sulfide moiety of this compound.(ABSTRACT TRUNCATED AT 250 WORDS)
利用电子自旋共振（ESR）自旋捕集技术，研究了在pH 7.4条件下，亚硫酸钠、亚硫酸镍（II）和硫化亚镍（Ni3S2）被环境氧气或过氧化氢氧化产生自由基的情况。所用的自旋捕集剂是5,5-二甲基-1-吡咯啉-N-氧化物（DMPO）。在环境氧气存在下，单独的亚硫酸钠溶液由于亚硫酸盐的自氧化主要产生三氧化硫阴离子自由基（.SO3-）。添加氯化镍（II）[Ni（II）]使.SO3-的产量提高了约4倍。在螯合剂如四甘氨酸、组氨酸、β-丙氨酰-3-甲基-L-组氨酸（鹅肌肽）、β-L-组氨酸（肌肽）、γ-氨基丁酰-L-组氨酸（高肌肽）、谷胱甘肽和青霉胺存在的情况下，亚硫酸盐与Ni（II）一起孵育对这种增强没有任何显著影响。相比之下，白蛋白，尤其是甘氨酰甘氨酰组氨酸（GlyGlyHis），分别使Ni（II）的增强作用提高了1.4倍和4倍。对自旋加合物光谱的计算机模拟分析和甲酸清除实验表明，亚硫酸钠、Ni（II）和GlyGlyHis的混合物产生了羟基（.OH）自由基和.SO3-自由基，比例约为1:2。自由基自旋加合物强度在约5分钟内达到饱和水平。去铁胺可使自由基加合物的产量略有降低，而二乙烯三胺五乙酸（DTPA）则可使其大幅降低。在空气和GlyGlyHis存在下，难溶性亚硫酸镍（II）的水悬浮液产生了表面定位的.SO3-和.OH自由基。在GlyGlyHis和H2O2存在下，Ni3S2悬浮液中也产生了相同的自由基，表明该化合物的硫化物部分被氧化产生了亚硫酸盐。（摘要截断于250字）
