Development And Application Of Chemical Modification-assisted Proteomic Strategies

To address the problems in proteomics research, such as high complexities of peptide mixtures from samples, low confident level of protein identification, and difficulties in obtaining terminal information of proteins, four strategies for the enrichment and identification of signature peptides were developed based on sulfonation modification, homolog labeling, chromatographic or electrophoresis separation and mass spectrometric identification. Terminal peptides or histidine-containing peptides from model protein mixture were specifically enriched and identified by these methods to decrease the complexity of peptide mixture and the interference from non-targeted peptides and to facilitate peptide sequencing and protein identification. Four methods were separately introduced in four chapters. The methods described in the former two chapters were developed and used in shotgun strategy to enrich terminal peptides or histidine peptides from total digest of protein mixture to decrease the complexity of peptide mixture while the strategies introduced in the latter two were used in 2D gel to selectively identify N-terminal peptide in peptide mass fingerprinting for protein identification.It was the first time that sulfonation modification and homolog labeling had been used to enrich and identify terminal peptides or histidine-containing peptides in our knowledge. Based on the researches above, 2 papers were published in Chinese, 4 manuscripts were prepared in English, one project was granted from National Natural Science Fund Committee, and 4 patents were applied. The results from model proteins showed that sample complexities were reduced, the abundances of terminal peptides were increased, peptide sequencing and identification were improved by enriching and identifying the terminal peptides or histidine peptides with the methods, which suggest the potential applications of these methods in proteomics.