학술논문
Site-specific separation and detection of phosphopeptide isomers with p H-mediated stacking capillary electrophoresis-electrospray ionization-tandem mass spectrometry.
Document Type
Article
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ISSN
1615-9306
Abstract
This study reported a p H-mediated stacking CE coupled with ESI MS/ MS method to determine the phosphorylation sites of three synthetic phosphopeptides containing structural isomers. These phosphopeptides mimic the phosphopeptides (amino acid residues 12-25) derived from the trypsin-digested products of human lamin A/ C protein. The LODs were determined to be 118, 132 and 1240 fmol for SGAQASS19 Tp PL22 SPTR, SGAQASS19 TPL22 Sp PTR, and SGAQASS19 Tp PL22 Sp P TR, respectively. The established method was employed to analyze the phosphorylation sites of the trypsin-digested products of glutathione S-transferase-lamin A/ C (1-57) fusion protein that had been phosphorylated in vitro by cyclin-dependent kinase 1. The results indicated that this method is feasible to specifically determine the phosphorylation site from phosphopeptide isomers in the trypsin-digested products of a kinase-catalyzed phosphoprotein, which should benefit the investigation of protein kinase-mediated cellular signal transduction. [ABSTRACT FROM AUTHOR]