State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, 18 Shuangqing Road, Beijing 100085, China.
Biosens Bioelectron. 2011 Jan 15;26(5):2292-6. doi: 10.1016/j.bios.2010.09.054. Epub 2010 Oct 8.
A simple and sensitive electrochemical biosensor was used to detect tyrosine oxidation induced by hydroxyl radicals generated by Fenton reaction (Fe(2+)/H(2)O(2)). Poly(glu, tyr) (4:1) peptides were immobilized on indium tin oxide (ITO) electrode surface via layer-by-layer assembly technique, and Os(bpy)(3)(2+)-mediated tyrosine oxidation current was employed as the signal reporter of the biosensor. It was found that the electrochemical signal of the peptide decreased markedly after incubation with Fenton reagents. Interestingly, L-dopa, the oxidation product of tyrosine, was likely to form complexes with Fe(III), which could suppress the electro-oxidation of L-dopa and resulted in decrease of current response. Our results indicate that the peptide damage involved two steps and was a second-order reaction. X-ray photoelectron spectroscopy was used to quantitatively determine nitrogen elemental percentage on peptide-coated electrode surface, which eliminated the possibility that signal decrease was caused by peptide backbone cleavage. Moreover, the lowest concentration of Fenton reagents that could be detected was 10 μM Fe(2+) or H(2)O(2), similar to the level in vivo. We suggest that the biosensor can be used to detect protein damage induced by Fenton reaction.
一种简单灵敏的电化学生物传感器被用于检测由芬顿反应（Fe(2+)/H(2)O(2)）产生的羟基自由基诱导的酪氨酸氧化。聚（谷氨酸，酪氨酸）（4:1）肽通过层层自组装技术固定在铟锡氧化物（ITO）电极表面，并且 Os(bpy)(3)(2+)-介导的酪氨酸氧化电流被用作生物传感器的信号报告器。结果发现，肽与芬顿试剂孵育后，其电化学信号明显降低。有趣的是，酪氨酸的氧化产物 L-多巴可能与 Fe(III)形成配合物，这可以抑制 L-多巴的电氧化，导致电流响应降低。我们的结果表明，肽的损伤涉及两个步骤，是一个二级反应。X 射线光电子能谱被用于定量确定肽涂覆电极表面上的氮元素百分比，这排除了信号降低是由肽主链断裂引起的可能性。此外，能够检测到的最低浓度的芬顿试剂为 10 μM Fe(2+)或 H(2)O(2)，与体内水平相当。我们建议该生物传感器可用于检测由芬顿反应引起的蛋白质损伤。
