An optimized magnetite microparticle-based phosphopeptide enrichment strategy for identifying multiple phosphorylation sites in an immunoprecipitated protein.
An optimized magnetite microparticle-based phosphopeptide enrichment strategy for identifying multiple phosphorylation sites in an immunoprecipitated protein.
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DOI：
10.1016/j.ab.2010.08.002
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发表时间：
2011
影响因子：
2.9
通讯作者：
Yi Huang;Q. Shi;Chia‐Kuang Tsung;H. Gunawardena;Ling Xie;Yanbao Yu;Hongjun Liang;Pengyuan Yang;G. Stucky;Xian Chen
中科院分区：
文献类型：
--
作者：
Yi Huang;Q. Shi;Chia‐Kuang Tsung;H. Gunawardena;Ling Xie;Yanbao Yu;Hongjun Liang;Pengyuan Yang;G. Stucky;Xian Chen
To further improve the selectivity and throughput of phosphopeptide analysis for the samples from real-time cell lysates, here we demonstrate a highly efficient method for phosphopeptide enrichment via newly synthesized magnetite microparticles and the concurrent mass spectrometric analysis. The magnetite microparticles show excellent magnetic responsivity and redispersibility for a quick enrichment of those phosphopeptides in solution. The selectivity and sensitivity of magnetite microparticles in phosphopeptide enrichment are first evaluated by a known mixture containing both phosphorylated and nonphosphorylated proteins. Compared with the titanium dioxide-coated magnetic beads commercially available, our magnetite microparticles show a better specificity toward phosphopeptides. The selectively-enriched phosphopeptides from tryptic digests of β-casein can be detected down to 0.4fmolμl−1, whereas the recovery efficiency is approximately 90% for monophosphopeptides. This magnetite microparticle-based affinity technology with optimized enrichment conditions is then immediately applied to identify all possible phosphorylation sites on a signal protein isolated in real time from a stress-stimulated mammalian cell culture. A large fraction of peptides eluted from the magnetic particle enrichment step were identified and characterized as either single- or multiphosphorylated species by tandem mass spectrometry. With their high efficiency and utility for phosphopeptide enrichment, the magnetite microparticles hold great potential in the phosphoproteomic studies on real-time samples from cell lysates.
