Table of Contents
International Journal of Proteomics
Volume 2011 (2011), Article ID 739615, 11 pages
Research Article

Combined Use of a Solid-Phase Hexapeptide Ligand Library with Liquid Chromatography and Two-Dimensional Difference Gel Electrophoresis for Intact Plasma Proteomics

1Division of Pharmacoproteomics, National Cancer Center Research Institute, Chuo-ku, Tokyo 104-0045, Japan
2Laboratory of Genome Biology, Department of Biological Science and Technology, Tokyo University of Science, Tokyo 278-8510, Japan
3Laboratory of Proteome Research, National Institute of Biomedical Innovation, Osaka 567-0085, Japan

Received 2 May 2011; Accepted 9 June 2011

Academic Editor: David E. Misek

Copyright © 2011 Tatsuo Hagiwara et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The intact plasma proteome is of great interest in biomarker studies because intact proteins reflect posttranslational protein processing such as phosphorylation that may correspond to disease status. We examined the utility of a solid-phase hexapeptide ligand library in combination with conventional plasma proteomics modalities for comprehensive profiling of intact plasma proteins. Plasma proteins were sequentially fractionated using depletion columns for albumin and immunoglobulin, and separated using an anion-exchange column. Proteins in each fraction were treated with a solid-phase hexapeptide ligand library and compared to those without treatment. Two-dimensional difference gel electrophoresis demonstrated an increased number of protein spots in the treated samples. Mass spectrometric studies of these protein spots with unique intensity in the treated samples resulted in the identification of high- and medium-abundance proteins. Our results demonstrated the possible utility of a solid-phase hexapeptide ligand library to reveal greater number of intact plasma proteins. The characteristics of proteins with unique affinity to the library remain to be clarified by more extensive mass spectrometric protein identification, and optimized protocols should be established for large-scale plasma biomarker studies.