In vitro reactive oxygen species production by histatins and copper(I,II)
In vitro reactive oxygen species production by histatins and copper(I,II)
复制标题
DOI：
10.1007/s00775-008-0444-x
复制
发表时间：
2009-02-01
影响因子：
3
通讯作者：
Nicholas, Kenneth M.
中科院分区：
文献类型：
--
作者：
Houghton, Eric A.;Nicholas, Kenneth M.
已经评估了富含组氨酸的肽——组氨素 - 5（Hst - 5）和组氨素 - 8（Hst - 8）在铜催化抗坏血酸和半胱氨酸氧化过程中支持活性氧生成的能力。通过反应后的Amplex Red检测确定，含有Cu(II)、Hst - 8或Hst - 5以及还原剂（抗坏血酸或半胱氨酸）的水溶液会产生大量过氧化氢（70 - 580摩尔/摩尔Cu/小时）。当反应在超氧化物歧化酶存在下进行时，产生的总过氧化氢量减少，在有肽存在的情况下减少得更多（高达50%），这表明超氧化物在这些反应中是中间产物。另一方面，叠氮化钠或甲酸钠（羟基自由基捕获剂）的存在对Cu - Hst体系的总过氧化氢产生没有明显影响。在半胱氨酸 - Cu(II)反应中使用5 - (2,2 - 二甲基 - 1,3 - 丙氧基环磷酰基) - 5 - 甲基 - 1 - 吡咯啉N - 氧化物（CYPMPO）进行的电子顺磁共振（EPR）自旋捕获研究表明，在Hst - 8存在的情况下，会形成CYPMPO - 氢过氧基和CYPMPO - 羟基自由基加合物，而单独使用Cu时仅观察到后者。
The ability of the histidine-rich peptides, histatin-5 (Hst-5) and histatin-8 (Hst-8), to support the generation of reactive oxygen species during the Cu-catalyzed oxidation of ascorbate and cysteine has been evaluated. High levels of hydrogen peroxide (70-580 mol/mol Cu/h) are produced by aqueous solutions containing Cu(II), Hst-8 or Hst-5, and a reductant, either ascorbate or cysteine, as determined by the postreaction Amplex Red assay. When the reactions are conducted in the presence of superoxide dismutase, the total hydrogen peroxide produced is decreased, more so in the presence of the peptides ( up to 50%), suggesting the intermediacy of superoxide in these reactions. On the other hand, the presence of sodium azide or sodium formate, traps for hydroxyl radicals, has no appreciable effect on the total hydrogen peroxide production for the Cu-Hst systems. EPR spin-trapping studies using 5-(2,2-dimethyl-1,3-propoxy cyclophosphoryl)-5-methyl-1-pyrrolineN-oxide (CYPMPO) in the cysteine Cu( II) reactions reveal the formation of the CYPMPO hydroperoxyl and CYPMPO-hydroxyl radical adducts in the presence of Hst-8, whereas only the latter was observed with Cu alone.