SEC-ICP-MS and ESI-MS/MS for analyzing in vitro and in vivo Cd-phytochelatin complexes in a Cd-hyperaccumulator Brassica chinensis
SEC-ICP-MS and ESI-MS/MS for analyzing in vitro and in vivo Cd-phytochelatin complexes in a Cd-hyperaccumulator Brassica chinensis
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SEC-ICP-MS 和 ESI-MS/MS 用于分析 Cd 超积累植物甘蓝中的 Cd-植物螯合素复合物的体外和体内
DOI：
10.1039/b707830g
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发表时间：
2007-01-01
影响因子：
3.4
通讯作者：
Wang, Qiuquan
中科院分区：
文献类型：
--
作者：
Chen, Liqin;Guo, Yifei;Wang, Qiuquan
本研究利用SEC-ICP-MS和ESI-MS/MS对Cd胁迫下的超积累植物小白菜体内和体外合成的Cd-植物螯合素（PC）复合物进行了表征。用CdCl_2与中华绒螯蟹体外合成Cd-PC复合物，观察到CdGS（1-2）、（CdGS）（2）、Cd_（1 - 2）PC_2、Cd_（1 - 3）PC_3、Cd_（1 - 3）PC_4和Cd_（1 - 3）PC_5的形成。此外，首次在Cd胁迫的B提取物中检测到体内CdPC 3和CdPC 4复合物，以及无Cd PC（n = 2-5）和desGlu-PC 3。并通过相应的同位素峰分布和MS/ MS谱图进行了确证。用氮饱和碳酸氢铵缓冲液（pH7.8）代替Tris-HCl和磷酸盐缓冲液作为合适的移动的流动相，以稳定Cd-PC络合物，并测定了其电化学发光强度。有效地避免了SEC分级分离过程中PC类似物的可能氧化。本研究结果为阐明PC在植物防御Cd胁迫机制中的重要作用提供了明确的证据。SEC-ICP-MS和ESI-MS/ MS是筛选和鉴定体内金属肽的强有力的技术，具有准确的同位素分配，在金属毒理学研究中。
In this study, in vitro synthesized Cd-phytochelatin (PC) complexes and in vivo Cd -PC complexes in Cd-stressed Brassica chinensis, which has been identified as a Cd hyperaccumulator, were characterized using SEC-ICP-MS and ESI-MS/ MS. The PCs (n = 1 -5) obtained from Cd-stressed B. chinensis together with CdCl2 were used to synthesize the in vitro Cd -PC complexes, and the formation of CdGS(1-2), (CdGS)(2), Cd1-2PC2, Cd1-3PC3, Cd1-3PC4 and Cd1-3PC5 was observed. In addition, for the first time, in vivo CdPC3 and CdPC4 complexes, as well as Cd-free PCs (n = 2-5) and desGlu-PC3 were detected in the extracts of Cd-stressed B. chinensis and confirmed by means of their corresponding isotopic peak distribution and MS/ MS spectra. Nitrogen saturated ammonium bicarbonate buffer (pH 7.8), instead of Tris-HCl and phosphate buffer, was used as a suitable mobile phase in order to stabilize the Cd -PC complexes and e. ectively avoid possible oxidation of PC analogues during SEC fractionation. Results obtained in this study give definite evidence elucidating the important roles which PCs play in plant defensive mechanisms to Cd stress. SEC-ICP-MS and ESI-MS/ MS were demonstrated as powerful and promising techniques for screening and identifying the in vivo metallopeptides, with accurate isotopic distribution assignment, in metal toxicological studies.